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Yang PC, Jeng MT, Yarov-Yarovoy V, Santana LF, Vorobyov I, Clancy CE. Toward Digital Twin Technology for Precision Pharmacology. JACC Clin Electrophysiol 2024; 10:359-364. [PMID: 38069976 DOI: 10.1016/j.jacep.2023.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/26/2023] [Accepted: 10/20/2023] [Indexed: 03/01/2024]
Abstract
The authors demonstrate the feasibility of technological innovation for personalized medicine in the context of drug-induced arrhythmia. The authors use atomistic-scale structural models to predict rates of drug interaction with ion channels and make predictions of their effects in digital twins of induced pluripotent stem cell-derived cardiac myocytes. The authors construct a simplified multilayer, 1-dimensional ring model with sufficient path length to enable the prediction of arrhythmogenic dispersion of repolarization. Finally, the authors validate the computational pipeline prediction of drug effects with data and quantify drug-induced propensity to repolarization abnormalities in cardiac tissue. The technology is high throughput, computationally efficient, and low cost toward personalized pharmacologic prediction.
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Affiliation(s)
- Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California, USA
| | - Mao-Tsuen Jeng
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California, USA
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California, USA; Department of Anesthesiology and Pain Medicine, University of California-Davis, Davis, California, USA
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California, USA
| | - Igor Vorobyov
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California, USA; Department of Pharmacology, University of California-Davis, Davis, California, USA.
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California, USA; Department of Pharmacology, University of California-Davis, Davis, California, USA; Center for Precision Medicine, University of California-Davis, Davis, California, USA.
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2
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Weinberg SH, Hund TJ. Building A Pipeline for Precision Antiarrhythmic Therapy. JACC Clin Electrophysiol 2024; 10:365-366. [PMID: 38180434 DOI: 10.1016/j.jacep.2023.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 11/24/2023] [Indexed: 01/06/2024]
Affiliation(s)
- Seth H Weinberg
- Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA
| | - Thomas J Hund
- Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA; Division of Cardiovascular Medicine, Department of Internal Medicine, Ohio State University, Columbus, Ohio, USA.
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Treatment of atrial fibrillation. Med Lett Drugs Ther 2024; 66:1-8. [PMID: 38180321 DOI: 10.58347/tml.2024.1693a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in the world. Risk factor modification, anticoagulation, rhythm control, and rate control are the four pillars of its management. American College of Cardiology/American Heart Association (ACC/AHA) guidelines on management of AF were updated recently.
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Yagnala N, Moreland-Head L, Zieminski JJ, Mara K, Macielak S. Assessment of Dofetilide or Sotalol Tolerability in the Elderly. J Cardiovasc Pharmacol Ther 2024; 29:10742484231224536. [PMID: 38258374 DOI: 10.1177/10742484231224536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Background: Dofetilide and sotalol are potassium channel antagonists that require inpatient QTc monitoring during initiation, due to increased risk of fatal arrhythmias. Elderly patients are especially subject to an increased risk of fatal arrhythmias due to polypharmacy, comorbidities, and physiologic cardiac changes with aging. This study will describe the tolerability and risk factors associated with the initiation of sotalol or dofetilide in patients ≥80 years of age. Methodology: This is a multicenter, retrospective, descriptive study of patients ≥80 years old who were initiated on either dofetilide or sotalol between May 8, 2018 and July 31, 2021 at institutions within the Mayo Clinic Health System. The percentage of patients who received nonpackage insert recommended doses was identified. Incidence of and reasons for dose reductions or discontinuations due to safety-related events or clinical concerns during the initial loading period were collected. Results: The final analysis included 104 patients. The majority of patients (75%) received nonstandard initial doses of dofetilide or sotalol based on baseline estimated creatinine clearance or QTc. Overall, 39% (N = 41) of patients experienced a dose reduction or discontinuation due to a safety-related event or concern. Patients who received nonstandard initial doses of dofetilide or sotalol had 4.7 times greater odds of experiencing a safety-related event requiring dose reduction or discontinuation. Conclusion: Following package insert dosing in elderly patients increases safety and tolerability relative to more aggressive dosing of dofetilide or sotalol.
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Affiliation(s)
- Nikitha Yagnala
- Pharmacy Resident, Department of Pharmacy, Mayo Clinic, Rochester, MN, USA
| | | | | | - Kristin Mara
- Senior Biostatistician, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Shea Macielak
- Pharmacist, Department of Pharmacy, Mayo Clinic, Rochester, MN, USA
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Wann DG, Medoff BS, Mehdi NUHA, Sezer A, Thoma FW, Mulukutla S, Bhonsale A, Estes NM, Saba S, Jain SK. Dofetilide use is not associated with increased mortality in patients with left ventricular hypertrophy and atrial fibrillation. J Cardiovasc Electrophysiol 2023; 34:447-452. [PMID: 36335642 DOI: 10.1111/jce.15733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 09/25/2022] [Accepted: 10/17/2022] [Indexed: 11/08/2022]
Abstract
BACKGROUND Left ventricular hypertrophy (LVH) is common in patients with atrial fibrillation (AF), however, many antiarrhythmic drugs (AADs) are contraindicated. US guidelines recommend avoiding pure class III antiarrhythmics such as dofetilide in patients with significant LVH due to concern for an increased risk of death, however, clinical data is lacking. We sought to determine if dofetilide use was associated with increased mortality in patients with LVH. METHODS Patients ≥18 years of age with AF and LVH ≥ 1.4 cm were included. A group of patients treated with dofetilide and a control group of patients without a history of AAD use were propensity matched. The primary outcome was all-cause mortality at 3 years and secondary outcomes were total number of all-cause hospitalizations and hospitalizations related to AF. RESULTS There were 359 patients in each of the groups. Baseline variables were well-matched. The primary outcome of all-cause mortality occurred in 7% of patients in the dofetilide group and 12% of patients in the control group (hazard ratio: 0.90, 95% confidence interval: 0.53-1.53). Total all-cause hospitalizations were higher in the control group but hospitalizations for AF were no different. CONCLUSIONS In a propensity-matched cohort of 718 patients with AF and LVH, dofetilide was not associated with increased mortality at 3 years. Our study adds to prior data demonstrating the safety of dofetilide in this population despite guideline recommendations against its use. Given the limited options for AF management in LVH patients, dofetilide may be reasonable for symptomatic AF management.
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Affiliation(s)
- Daniel G Wann
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Brent S Medoff
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Noor-Ul-Huda A Mehdi
- Internal Medicine, Medstar Washington Hospital Center, District of Columbia, Washington, USA
| | - Ahmet Sezer
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Floyd W Thoma
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Suresh Mulukutla
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Aditya Bhonsale
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Na Mark Estes
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Samir Saba
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Sandeep K Jain
- Center for Atrial Fibrillation, Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
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Crosby J, Bhopalwala H, Kharawala A, Dewaswala N, Ganti SS, Bhopalwala A. Refractory Torsades de Pointes Due to Dofetilide Overdose. J Investig Med High Impact Case Rep 2021; 9:23247096211056492. [PMID: 34894807 PMCID: PMC8672374 DOI: 10.1177/23247096211056492] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Dofetilide, a class III antiarrhythmic, is widely used in the treatment of cardiac arrhythmias. Antiarrhythmic drugs can have a long duration of action that prolongs the QT interval. This causes bradycardia that predisposes to R-on-T phenomenon subsequently leading to torsades de pointes (TdP). This necessitates constant monitoring to prevent or treat ventricular arrhythmias or bradycardia associated with cardiac medications. Although extremely rare, dofetilide overdose has been described in the literature. However, no evidence found in the current literature required prolonged intervention after the initial acute stabilization, leading to scarcity of data for treatment of ongoing dofetilide overdose. We present the case of an intentional dofetilide overdose in a 61-year-old Caucasian woman with a history of congestive heart failure, atrial fibrillation, stage IIIb chronic kidney disease, diabetes mellitus type II, hypothyroidism, morbid obesity, and hypertension that required extensive interventions for refractory TdP that lasted 4 days. Therapeutic as well as excess dosage of dofetilide can lead to TdP, which is usually controlled by decreasing the dose or terminating drug administration. If the arrhythmia is not resolved, guidelines recommend management with activated charcoal if ingestion is within 15 minutes, followed by administration of 2 g IV (intravenous) magnesium and addressing the electrolyte imbalance. However, if the arrhythmia is persistent due to ongoing dofetilide toxicity, isoproterenol is given as a bridge to overdrive pacing and dopamine is used as an alternative to isoproterenol.
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Affiliation(s)
- James Crosby
- Appalachian Regional Healthcare, Whitesburg, KY, USA
| | | | | | - Nakeya Dewaswala
- University of Kentucky Albert B. Chandler Hospital, Lexington, USA
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Shantha G, Chugh A, Crawford T, Latchamsetty R, Ghanbari H, Ghannam M, Liang J, Batul A, Chung E, Saeed M, Cunnane R, Jongnarangsin K, Bogun F, Pelosi F, Morady F, Oral H. Comparative Efficacy of Dofetilide Versus Amiodarone in Patients With Atrial Fibrillation. JACC Clin Electrophysiol 2021; 7:642-648. [PMID: 33812835 DOI: 10.1016/j.jacep.2020.11.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/16/2020] [Accepted: 11/26/2020] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The study's goal was to compare the efficacy and safety of dofetilide (DOF) versus amiodarone (AMIO) in patients with atrial fibrillation (AF). BACKGROUND Comparative efficacy of DOF versus AMIO in patients with AF has not been well established. In addition, proarrhythmia has been a concern with DOF therapy. METHODS Rhythm control was attempted by using DOF in 657 consecutive patients (mean age 72 ± 9 years; 35% women) with AF (n = 528) or atrial flutter and AF (n = 129) between January 2014 and December 2018. RESULTS DOF was successfully initiated in 573 (87%) of 657 patients, including 510 (89%) with persistent AF and 63 (11%) with paroxysmal AF. During a mean follow-up of 19 ± 7 months, sinus rhythm was maintained in 361 (63%) of the 573 DOF-treated patients. At 12 months, patients on DOF had a similar likelihood of experiencing recurrent atrial arrhythmias compared with the 2,476 consecutive patients treated with AMIO for rhythm control during the study period (37% vs. 39%; p = 0.56). The efficacy of DOF and AMIO was also similar in specific subgroups of patients, including patients >75 years of age, with a low left ventricular ejection fraction, obesity, renal insufficiency, and prior catheter ablation for AF. Among patients with atypical atrial flutter, likelihood of recurrent atrial flutter was similar between the DOF (43 of 108 [40%]) and AMIO (211 of 555 [38%]; p = 0.69) groups. CONCLUSIONS When properly initiated and monitored, DOF has efficacy comparable to that of amiodarone for rhythm control in patients with AF.
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Affiliation(s)
- Ghanshyam Shantha
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Aman Chugh
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Thomas Crawford
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Rakesh Latchamsetty
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Hamid Ghanbari
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael Ghannam
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Jackson Liang
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Atiqa Batul
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Eugene Chung
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Mohammed Saeed
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Ryan Cunnane
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Krit Jongnarangsin
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Frank Bogun
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Frank Pelosi
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Fred Morady
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Hakan Oral
- Cardiac Arrhythmia Service, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
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Cicirale C, Jackson J, Gothard D. Safety of Inpatient Dofetilide Initiation per Cardiology Services: A Retrospective Review. J Pharm Pract 2021; 35:593-598. [PMID: 33736527 DOI: 10.1177/08971900211000212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Dofetilide is an antiarrhythmic medication that has the potential to cause life threatening arrhythmias, such as Torsade de pointes. The 2014 ACC/AHA/HRS guidelines for the management of patients with atrial fibrillation state that patients need to meet certain criteria to be initiated on dofetilide. Patients who are not initiated on this therapy according to the guideline criteria are likely to be at higher risk of adverse reactions. METHODS This is a single center, retrospective chart review of patients who were initiated on dofetilide from July 2016-December 2019. Patients included in the study were initiated on dofetilide as a new antiarrhythmic and monitored inpatient for 3 days. The primary outcome was a composite of incidence of cardiac arrhythmias, cardiac arrest, cardiac death, and cardiac related hospital readmission. RESULTS There were 224 patients included in the analysis: 190 patients who were initiated on dofetilide inappropriately and 34 that were initiated appropriately. The primary outcome (composite of cardiac arrhythmia, cardiac arrest, cardiac death, and hospital readmission) was statistically significant with more patients experiencing an outcome in the group initiated inappropriately. CONCLUSIONS Patients are placed at a higher risk of adverse reactions when this potentially dangerous antiarrhythmic medication is not used according to the protocol set forth by the guidelines. Practitioners should use caution when prescribing dofetilide. Other antiarrhythmic medications or non-pharmacologic options should be considered due to the incidence of these dangerous adverse reactions.
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Boulay E, Troncy E, Accardi MV, Pugsley MK, Downey AM, Miraucourt L, Huang H, Menard A, Tan W, Dubuc-Mageau M, Sanfacon A, Guerrier M, Authier S. Confounders and Pharmacological Characterization When Using the QT, JTp, and Tpe Intervals in Beagle Dogs. Int J Toxicol 2020; 39:530-541. [PMID: 33063577 DOI: 10.1177/1091581820954865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Corrected QT (QTc) interval is an essential proarrhythmic risk biomarker, but recent data have identified limitations to its use. The J to T-peak (JTp) interval is an alternative biomarker for evaluating drug-induced proarrhythmic risk. The aim of this study was to evaluate pharmacological effects using spatial magnitude leads and DII electrocardiogram (ECG) leads and common ECG confounders (ie, stress and body temperature changes) on covariate adjusted QT (QTca), covariate adjusted JTp (JTpca), and covariate adjusted T-peak to T-end (Tpeca) intervals. METHODS Beagle dogs were exposed to body hyper- (42 °C) or hypothermic (33 °C) conditions or were administered epinephrine to assess confounding effects on heart rate corrected QTca, JTpca, and Tpeca intervals. Dofetilide (0.1, 0.3, 1.0 mg/kg), ranolazine (100, 140, 200 mg/kg), and verapamil (7, 15, 30, 43, 62.5 mg/kg) were administered to evaluate pharmacological effects. RESULTS Covariate adjusted QT (slope -12.57 ms/°C) and JTpca (-14.79 ms/°C) were negatively correlated with body temperature but Tpeca was minimally affected. Epinephrine was associated with QTca and JTpca shortening, which could be related to undercorrection in the presence of tachycardia, while minimal effects were observed for Tpeca. There were no significant ECG change following ranolazine administration. Verapamil decreased QTca and JTpca intervals and increased Tpeca, whereas dofetilide increased QTca and JTpca intervals but had inconsistent effects on Tpeca. CONCLUSION Results highlight potential confounders on QTc interval, but also on JTpca and Tpeca intervals in nonclinical studies. These potential confounding effects may be relevant to the interpretation of ECG data obtained from nonclinical drug safety studies with Beagle dogs.
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Affiliation(s)
- Emmanuel Boulay
- Charles River Laboratories, Laval, Quebec, Canada.,70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Eric Troncy
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | | | | | | | | | - Hai Huang
- Charles River Laboratories, Laval, Quebec, Canada
| | | | - Wendy Tan
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | | | - Audrey Sanfacon
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Mireille Guerrier
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Simon Authier
- Charles River Laboratories, Laval, Quebec, Canada.,70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
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Árpádffy-Lovas T, Husti Z, Baczkó I, Varró A, Virág L. Different effects of amiodarone and dofetilide on the dispersion of repolarization between well-coupled ventricular and Purkinje fibers 1. Can J Physiol Pharmacol 2020; 99:48-55. [PMID: 32692935 DOI: 10.1139/cjpp-2020-0234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased transmural dispersion of repolarization is an established contributing factor to ventricular tachyarrhythmias. In this study, we evaluated the effect of chronic amiodarone treatment and acute administration of dofetilide in canine cardiac preparations containing electrotonically coupled Purkinje fibers (PFs) and ventricular muscle (VM) and compared the effects to those in uncoupled PF and VM preparations using the conventional microelectrode technique. Dispersion between PFs and VM was inferred from the difference in the respective action potential durations (APDs). In coupled preparations, amiodarone decreased the difference in APDs between PFs and VM, thus decreasing dispersion. In the same preparations, dofetilide increased the dispersion by causing a more pronounced prolongation in PFs. This prolongation was even more emphasized in uncoupled PF preparations, while the effect in VM was the same. In uncoupled preparations, amiodarone elicited no change on the difference in APDs. In conclusion, amiodarone decreased the dispersion between PFs and VM, while dofetilide increased it. The measured difference in APD between cardiac regions may be the affected by electrotonic coupling; thus, studying PFs and VM separately may lead to an over- or underestimation of dispersion.
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Affiliation(s)
- Tamás Árpádffy-Lovas
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Zoltán Husti
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
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Kudaibergenova M, Guo J, Khan HM, Zahid F, Lees-Miller J, Noskov SY, Duff HJ. Allosteric Coupling Between Drug Binding and the Aromatic Cassette in the Pore Domain of the hERG1 Channel: Implications for a State-Dependent Blockade. Front Pharmacol 2020; 11:914. [PMID: 32694995 PMCID: PMC7338687 DOI: 10.3389/fphar.2020.00914] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 06/04/2020] [Indexed: 12/18/2022] Open
Abstract
Human-ether-a-go-go-related channel (hERG1) is the pore-forming domain of the delayed rectifier K+ channel in the heart which underlies the IKr current. The channel has been extensively studied due to its propensity to bind chemically diverse group of drugs. The subsequent hERG1 block can lead to a prolongation of the QT interval potentially leading to an abnormal cardiac electrical activity. The recently solved cryo-EM structure featured a striking non-swapped topology of the Voltage-Sensor Domain (VSD) which is packed against the pore-domain as well as a small and hydrophobic intra-cavity space. The small size and hydrophobicity of the cavity was unexpected and challenges the already-established hypothesis of drugs binding to the wide cavity. Recently, we showed that an amphipathic drug, ivabradine, may favorably bind the channel from the lipid-facing surface and we discovered a mutant (M651T) on the lipid facing domain between the VSD and the PD which inhibited the blocking capacity of the drug. Using multi-microseconds Molecular Dynamics (MD) simulations of wild-type and M651T mutant hERG1, we suggested the block of the channel through the lipid mediated pathway, the opening of which is facilitated by the flexible phenylalanine ring (F656). In this study, we characterize the dynamic interaction of the methionine-aromatic cassette in the S5-S6 helices by combining data from electrophysiological experiments with MD simulations and molecular docking to elucidate the complex allosteric coupling between drug binding to lipid-facing and intra-cavity sites and aromatic cassette dynamics. We investigated two well-established hERG1 blockers (ivabradine and dofetilide) for M651 sensitivity through electrophysiology and mutagenesis techniques. Our electrophysiology data reveal insensitivity of dofetilide to the mutations at site M651 on the lipid facing side of the channel, mirroring our results obtained from docking experiments. Moreover, we show that the dofetilide-induced block of hERG1 occurs through the intracellular space, whereas little to no block of ivabradine is observed during the intracellular application of the drug. The dynamic conformational rearrangement of the F656 appears to regulate the translocation of ivabradine into the central cavity. M651T mutation appears to disrupt this entry pathway by altering the molecular conformation of F656.
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Affiliation(s)
- Meruyert Kudaibergenova
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Jiqing Guo
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Hanif M Khan
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Farhan Zahid
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - James Lees-Miller
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Sergei Yu Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Henry J Duff
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
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Koene RJ, Menon V, Cantillon DJ, Dresing TJ, Martin DO, Kanj M, Saliba WI, Tarakji KG, Baranowski B, Hussein AA, Tchou PJ, Bhargava M, Callahan TD, Rickard JW, Niebauer MJ, Chung MK, Varma N, Wilkoff BL, Lindsay BD, Wazni OM. Clinical Outcomes and Characteristics With Dofetilide in Atrial Fibrillation Patients Considered for Implantable Cardioverter-Defibrillator. Circ Arrhythm Electrophysiol 2020; 13:e008168. [PMID: 32538135 DOI: 10.1161/circep.119.008168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Dofetilide is one of the only anti-arrhythmic agents approved for atrial fibrillation (AF) in patients with reduced left ventricular ejection fraction (LVEF). However, postapproval data and safety outcomes are limited. In this study, we assessed the incidence and predictors of LVEF improvement, safety, and outcomes in patients with AF with LVEF ≤35% without prior implantable cardioverter defibrillator, cardiac resynchronization therapy, or AF ablation. METHODS An analysis of 168 consecutive patients from 2007 to 2016 was performed. Incidences of adverse events, drug continuation, implantable cardioverter defibrillator and cardiac resynchronization therapy implantation, LVEF improvement (>35%) and recovery (≥50%), AF recurrence, and AF ablation were determined. Multivariable regression analysis to identify predictors of LVEF improvement/recovery was performed. RESULTS The mean age was 64±12 years. Dofetilide was discontinued before hospital discharge in 46 (27%) because of QT prolongation (14%), torsades de pointe or polymorphic ventricular tachycardia/fibrillation (6% [sustained 3%, nonsustained 3%]), ineffectiveness (5%), or other causes (3%). At 1 year, 43% remained on dofetilide. Freedom from AF was 42% at 1 year, and 40% underwent future AF ablation. LVEF recovered (≥50%) in 45% and improved to >35% in 73%. Predictors of LVEF improvement included presence of AF during echocardiogram (odds ratio, 4.22 [95% CI, 1.71-10.4], P=0.002), coronary artery disease (odds ratio, 0.35 [95% CI, 0.16-0.79], P=0.01), left atrial diameter (odds ratio, 0.52 per 1 cm increase [95% CI, 0.30-0.90], P=0.01), and LVEF (odds ratio, per 1% increase, 1.09 [95% CI, 1.02-1.16], P=0.006). The C statistic was 0.78. CONCLUSIONS In patients with LVEF ≤35%, who are potential implantable cardioverter defibrillator candidates, treated with dofetilide as an initial anti-arrhythmic strategy for AF, drug discontinuation rates were high, and many underwent future AF ablation. However, most patients had improvement in LVEF, obviating the need for primary prevention implantable cardioverter defibrillator.
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Affiliation(s)
- Ryan J Koene
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Vivek Menon
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Daniel J Cantillon
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Thomas J Dresing
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - David O Martin
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Mohamed Kanj
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Walid I Saliba
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Khaldoun G Tarakji
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Bryan Baranowski
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Ayman A Hussein
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Patrick J Tchou
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Mandeep Bhargava
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Thomas D Callahan
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - John W Rickard
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Mark J Niebauer
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Mina K Chung
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Niraj Varma
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Bruce L Wilkoff
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Bruce D Lindsay
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
| | - Oussama M Wazni
- Department of Cardiovascular Medicine, Electrophysiology Section, Cleveland Clinic, OH
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Diness JG, Abildgaard L, Bomholtz SH, Skarsfeldt MA, Edvardsson N, Sørensen US, Grunnet M, Bentzen BH. Inhibition of K Ca2 Channels Decreased the Risk of Ventricular Arrhythmia in the Guinea Pig Heart During Induced Hypokalemia. Front Pharmacol 2020; 11:749. [PMID: 32508659 PMCID: PMC7251152 DOI: 10.3389/fphar.2020.00749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/06/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Hypokalemia reduces the cardiac repolarization reserve. This prolongs the QT-interval and increases the risk of ventricular arrhythmia; a risk that is exacerbated by administration of classical class 3 anti-arrhythmic agents.Small conductance Ca2+-activated K+-channels (KCa2) are a promising new atrial selective target for treatment of atrial fibrillation. Under physiological conditions KCa2 plays a minor role in ventricular repolarization. However, this might change under hypokalemia because of concomitant increases in ventriculay -60r intracellur Ca2+. PURPOSE To study the effects of pharmacological KCa2 channel inhibition by the compounds AP14145, ICA, or AP30663 under hypokalemic conditions as compared to dofetilide and hypokalemia alone time-matched controls (TMC). METHODS The current at +10 mV was compared in HEK293 cells stably expressing KCa2.3 perfused first with normo- and then hypokalemic solutions (4 mM K+ and 2.5 mM K+, respectively). Guinea pig hearts were isolated and perfused with normokalemic (4 mM K+) Krebs-Henseleit solution, followed by perfusion with drug or vehicle control. The perfusion was then changed to hypokalemic solution (2.5 mM K+) in presence of drug. 30 animals were randomly assigned to 5 groups: ICA, AP14145, AP30663, dofetilide, or TMC. QT-interval, the interval from the peak to the end of the T wave (Tp-Te), ventricular effective refractory period (VERP), arrhythmia score, and ventricular fibrillation (VF) incidence were recorded. RESULTS Hypokalemia slightly increased KCa2.3 current compared to normokalemia. Application of KCa2 channel inhibitors and dofetilide prolonged the QT interval corrected for heart rate. Dofetilide, but none of the KCa2 channel inhibitors increased Tp-Te during hypokalemia. During hypokalemia 4/6 hearts in the TMC group developed VF (two spontaneously, two by S1S2 stimulation) whereas 5/6 hearts developed VF in the dofetilide group (two spontaneously, three by S1S2 stimulation). In comparison, 0/6, 1/6, and 1/6 hearts developed VF when treated with the KCa2 channel inhibitors AP30663, ICA, or AP14145, respectively. CONCLUSION Hypokalemia was associated with an increased incidence of VF, an effect that also seen in the presence of dofetilide. In comparison, the structurally and functionally different KCa2 channel inhibitors, ICA, AP14145, and AP30663 protected the heart from hypokalemia induced VF. These results support that KCa2 inhibition may be associated with a better safety and tolerability profile than dofetilide.
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Affiliation(s)
| | | | - Sofia Hammami Bomholtz
- Acesion Pharma, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mark Alexander Skarsfeldt
- Acesion Pharma, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nils Edvardsson
- Acesion Pharma, Copenhagen, Denmark
- Department of Molecular and Clinical Medicine/Cardiology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | | | - Bo Hjorth Bentzen
- Acesion Pharma, Copenhagen, Denmark
- Department of Molecular and Clinical Medicine/Cardiology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Citerni C, Kirchhoff J, Olsen LH, Sattler SM, Grunnet M, Edvardsson N, Bentzen BH, Diness JG. Inhibition of K Ca2 and K v11.1 Channels in Pigs With Left Ventricular Dysfunction. Front Pharmacol 2020; 11:556. [PMID: 32435191 PMCID: PMC7219273 DOI: 10.3389/fphar.2020.00556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/14/2020] [Indexed: 12/17/2022] Open
Abstract
Background Inhibition of KCa2 channels, conducting IKCa, can convert atrial fibrillation (AF) to sinus rhythm and protect against its induction. IKCa inhibition has been shown to possess functional atrial selectivity with minor effects on ventricles. Under pathophysiological conditions with ventricular remodeling, however, inhibiting IKCa can exhibit both proarrhythmic and antiarrhythmic ventricular effects. The aim of this study was to evaluate the effects of the IKCa inhibitor AP14145, when given before or after the IKr blocker dofetilide, on cardiac function and ventricular proarrhythmia markers in pigs with or without left ventricular dysfunction (LVD). Methods Landrace pigs were randomized into an AF group (n = 6) and two control groups: SHAM1 (n = 8) and SHAM2 (n = 4). AF pigs were atrially tachypaced (A-TP) for 43 ± 4 days until sustained AF and LVD developed. A-TP and SHAM1 pigs received 20 mg/kg AP14145 followed by 100 µg/kg dofetilide whereas SHAM2 pigs received the same drugs in the opposite order. Proarrhythmic markers such as short-term variability of QT (STVQT) and RR (STVRR) intervals, and the number of premature ventricular complexes (PVCs) were measured at baseline and after administration of drugs. The influence on cardiac function was assessed by measuring cardiac output, stroke volume, and relevant echocardiographic parameters. Results IKCa inhibition by AP14145 did not increase STVQT or STVRR in any of the pigs. IKr inhibition by dofetilide markedly increased STVQT in the A-TP pigs, but not in SHAM operated pigs. Upon infusion of AP14145 the number of PVCs decreased or remained unchanged both when AP14145 was infused after baseline and after dofetilide. Conversely, the number of PVCs increased or remained unchanged upon dofetilide infusion. Neither AP14145 nor dofetilide affected relevant echocardiographic parameters, cardiac output, or stroke volume in any of the groups. Conclusion IKCa inhibition with AP14145 was not proarrhythmic in healthy pigs, or in the presence of LVD resulting from A-TP. In pigs already challenged with 100 µg/kg dofetilide there were no signs of proarrhythmia when 20 mg/kg AP14145 were infused. KCa2 channel inhibition did not affect cardiac function, implying that KCa2 inhibitors can be administered safely also in the presence of LV dysfunction.
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Affiliation(s)
- Carlotta Citerni
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Acesion Pharma, Copenhagen, Denmark
| | | | - Lisbeth Høier Olsen
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark
| | - Stefan Michael Sattler
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiology, Heart Center, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | | | - Nils Edvardsson
- Acesion Pharma, Copenhagen, Denmark.,Department of Molecular and Clinical Medicine, Sahlgrenska Academy at Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Bo Hjorth Bentzen
- Biomedical Institute, University of Copenhagen, Copenhagen, Denmark.,Acesion Pharma, Copenhagen, Denmark
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15
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Abstract
BACKGROUND Patients initiated on sotalol and dofetilide require inpatient monitoring and dose adjustments due to risks of corrected QT (QTc) prolongation and Torsades de pointes (TdP). Patients may receive higher initial doses than recommended due to close monitoring by specialized practitioners. The objective of this study was to describe prescribing practices of sotalol and dofetilide and to compare safety outcomes between standard and nonstandard dosing strategies. METHODS This was a single-center retrospective analysis of adult inpatients who underwent sotalol or dofetilide initiation between June 1, 2015, and August 1, 2018. The end points of this study included the percentage of patients who received standard and nonstandard dosing, incidence of QTc prolongation (≥500 milliseconds or ≥15% from baseline), incidence of TdP, and dose reduction or medication discontinuation. RESULTS A total of 379 patients (195 sotalol and 184 dofetilide) were included in this analysis. There were 110 (56.4%) patients in the sotalol group and 111 (58.4%) patients in the dofetilide group that received nonstandard initial dosing. Nonstandard dosing was associated with a greater incidence of QTc prolongation compared to standard dosing (57.5% vs 43.0%, P = .005). Only one patient in the nonstandard dosing group experienced TdP. Patients initiated on nonstandard dosing required dose reduction or therapy discontinuation (37.6% vs 23.4%, P = .003) more frequently. CONCLUSION Higher than recommended initial doses of sotalol or dofetilide were associated with higher incidence of QTc prolongation and more frequent therapy modification.
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Affiliation(s)
- Clara Ting
- Department of Pharmacy Services, Brigham and Women's Hospital, Boston, MA, USA
| | - Rhynn Malloy
- Department of Pharmacy Services, Brigham and Women's Hospital, Boston, MA, USA
| | - Danielle Knowles
- Department of Pharmacy Services, Brigham and Women's Hospital, Boston, MA, USA
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16
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Morettini M, Peroni C, Sbrollini A, Marcantoni I, Burattini L. Classification of drug-induced hERG potassium-channel block from electrocardiographic T-wave features using artificial neural networks. Ann Noninvasive Electrocardiol 2019; 24:e12679. [PMID: 31347753 DOI: 10.1111/anec.12679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/09/2019] [Accepted: 06/03/2019] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Human ether-à-go-go-related gene (hERG) potassium-channel block represents a harmful side effect of drug therapy that may cause torsade de pointes (TdP). Analysis of ventricular repolarization through electrocardiographic T-wave features represents a noninvasive way to accurately evaluate the TdP risk in drug-safety studies. This study proposes an artificial neural network (ANN) for noninvasive electrocardiography-based classification of the hERG potassium-channel block. METHODS The data were taken from the "ECG Effects of Ranolazine, Dofetilide, Verapamil, and Quinidine in Healthy Subjects" Physionet database; they consisted of median vector magnitude (VM) beats of 22 healthy subjects receiving a single 500 μg dose of dofetilide. Fourteen VM beats were considered for each subject, relative to time-points ranging from 0.5 hr before to 14.0 hr after dofetilide administration. For each VM, changes in two indexes accounting for the early and the late phases of repolarization, ΔERD30% and ΔTS /A , respectively, were computed as difference between values at each postdose time-point and the predose time-point. Thus, the dataset contained 286 ΔERD30% -ΔTS /A pairs, partitioned into training, validation, and test sets (114, 29, and 143 pairs, respectively) and used as inputs of a two-layer feedforward ANN with two target classes: high block (HB) and low block (LB). Optimal ANN (OANN) was identified using the training and validation sets and tested on the test set. RESULTS Test set area under the receiver operating characteristic was 0.91; sensitivity, specificity, accuracy, and precision were 0.93, 0.83, 0.92, and 0.96, respectively. CONCLUSION OANN represents a reliable tool for noninvasive assessment of the hERG potassium-channel block.
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Affiliation(s)
- Micaela Morettini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Chiara Peroni
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Agnese Sbrollini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Ilaria Marcantoni
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Laura Burattini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
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17
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Ramirez RJ, Takemoto Y, Martins RP, Filgueiras-Rama D, Ennis SR, Mironov S, Bhushal S, Deo M, Rajamani S, Berenfeld O, Belardinelli L, Jalife J, Pandit SV. Mechanisms by Which Ranolazine Terminates Paroxysmal but Not Persistent Atrial Fibrillation. Circ Arrhythm Electrophysiol 2019; 12:e005557. [PMID: 31594392 DOI: 10.1161/circep.117.005557] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Ranolazine inhibits Na+ current (INa), but whether it can convert atrial fibrillation (AF) to sinus rhythm remains unclear. We investigated antiarrhythmic mechanisms of ranolazine in sheep models of paroxysmal (PxAF) and persistent AF (PsAF). METHODS PxAF was maintained during acute stretch (N=8), and PsAF was induced by long-term atrial tachypacing (N=9). Isolated, Langendorff-perfused sheep hearts were optically mapped. RESULTS In PxAF ranolazine (10 μmol/L) reduced dominant frequency from 8.3±0.4 to 6.2±0.5 Hz (P<0.01) before converting to sinus rhythm, decreased singularity point density from 0.070±0.007 to 0.039±0.005 cm-2 s-1 (P<0.001) in left atrial epicardium (LAepi), and prolonged AF cycle length (AFCL); rotor duration, tip trajectory, and variance of AFCL were unaltered. In PsAF, ranolazine reduced dominant frequency (8.3±0.5 to 6.5±0.4 Hz; P<0.01), prolonged AFCL, increased the variance of AFCL, had no effect on singularity point density (0.048±0.011 to 0.042±0.016 cm-2 s-1; P=ns) and failed to convert AF to sinus rhythm. Doubling the ranolazine concentration (20 μmol/L) or supplementing with dofetilide (1 μmol/L) failed to convert PsAF to sinus rhythm. In computer simulations of rotors, reducing INa decreased dominant frequency, increased tip meandering and produced vortex shedding on wave interaction with unexcitable regions. CONCLUSIONS PxAF and PsAF respond differently to ranolazine. Cardioversion in the former can be attributed partly to decreased dominant frequency and singularity point density, and prolongation of AFCL. In the latter, increased dispersion of AFCL and likely vortex shedding contributes to rotor formation, compensating for any rotor loss, and may underlie the inefficacy of ranolazine to terminate PsAF.
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Affiliation(s)
- Rafael J Ramirez
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Yoshio Takemoto
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Raphaël P Martins
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - David Filgueiras-Rama
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.).,Fundación Centro Nacional de Investigaciones Cardiovasculares, Carlos III (CNIC; D.F.-R., J.J.).,Centros de Investigación Biomédica en Red (CIBER) for Cardiovascular Diseases, Madrid, Spain (D.F.-R., J.J.)
| | - Steven R Ennis
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Sergey Mironov
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | - Sandesh Bhushal
- Department of Engineering, Norfolk State University, VA (S.B., M.D.)
| | - Makarand Deo
- Department of Engineering, Norfolk State University, VA (S.B., M.D.)
| | - Sridharan Rajamani
- Gilead Sciences, Foster City, CA (S.R., L.B.).,Currently: Amgen Inc, San Francisco, CA (S.R.)
| | - Omer Berenfeld
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
| | | | - José Jalife
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.).,Fundación Centro Nacional de Investigaciones Cardiovasculares, Carlos III (CNIC; D.F.-R., J.J.).,Centros de Investigación Biomédica en Red (CIBER) for Cardiovascular Diseases, Madrid, Spain (D.F.-R., J.J.)
| | - Sandeep V Pandit
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor (R.J.R., Y.T., R.P.M., D.F.-R., S.R.E., S.M., O.B., J.J., S.V.P.)
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Drugs for atrial fibrillation. Med Lett Drugs Ther 2019; 61:137-44. [PMID: 31599871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
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19
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Kirchhoff JE, Skarsfeldt MA, Muthukumarasamy KM, Simó-Vicens R, Bomholtz SH, Abildgaard L, Jespersen T, Sørensen US, Grunnet M, Bentzen BH, Diness JG. The K Ca2 Channel Inhibitor AP14145, But Not Dofetilide or Ondansetron, Provides Functional Atrial Selectivity in Guinea Pig Hearts. Front Pharmacol 2019; 10:668. [PMID: 31275147 PMCID: PMC6593233 DOI: 10.3389/fphar.2019.00668] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/23/2019] [Indexed: 11/13/2022] Open
Abstract
Background and Purpose: Prolongation of cardiac action potentials is considered antiarrhythmic in the atria but can be proarrhythmic in ventricles if the current carried by Kv11.1-channels (IKr) is inhibited. The current mediated by KCa2-channels, IKCa, is considered a promising new target for treatment of atrial fibrillation (AF). Selective inhibitors of IKr (dofetilide) and IKCa (AP14145) were used to compare the effects on ventricular and atrial repolarization. Ondansetron, which has been reported to be a potent blocker of both IKr and IKCa, was included to examine its potential atrial antiarrhythmic properties. Experimental Approach: The expression of KCa2- and Kv11.1-channels in the guinea pig heart was investigated using quantitative polymerase chain reaction (qPCR). Whole-cell patch clamp technique was used to investigate the effects of dofetilide, AP14145, and ondansetron on IKCa and/or IKr. The effect of dofetilide, AP14145, and ondansetron on atrial and ventricular repolarization was investigated in isolated hearts. A novel atrial paced in vivo guinea pig model was further validated using AP14145 and dofetilide. Key Results: AP14145 increased the atrial effective refractory period (AERP) without prolonging the QT interval with Bazett's correction for heart rate (QTcB) both ex vivo and in vivo. In contrast, dofetilide increased QTcB and, to a lesser extent, AERP in isolated hearts and prolonged QTcB with no effects on AERP in the in vivo guinea pig model. Ondansetron did not inhibit IKCa, but did inhibit IKr in vitro. Ondansetron prolonged ventricular, but not atrial repolarization ex vivo. Conclusion and Implications: IKCa inhibition by AP14145 selectively increases atrial repolarization, whereas IKr inhibition by dofetilide and ondansetron increases ventricular repolarization to a larger extent than atrial repolarization.
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Affiliation(s)
| | - Mark Alexander Skarsfeldt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kalai Mangai Muthukumarasamy
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rafel Simó-Vicens
- Acesion Pharma, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sofia Hammami Bomholtz
- Acesion Pharma, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Bo Hjorth Bentzen
- Acesion Pharma, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Tisdale JE, Jaynes HA, Overholser BR, Sowinski KM, Kovacs RJ. Progesterone pretreatment reduces the incidence of drug-induced torsades de pointes in atrioventricular node-ablated isolated perfused rabbit hearts. J Cardiovasc Electrophysiol 2019; 30:941-949. [PMID: 31006943 DOI: 10.1111/jce.13942] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/05/2019] [Accepted: 03/13/2019] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Higher progesterone concentrations are protective against drug-induced prolongation of ventricular repolarization. We tested the hypothesis that pretreatment with progesterone reduces the incidence of drug-induced torsades de pointes (TdP). METHODS AND RESULTS Female New Zealand white rabbits (2.5-3.2 kg) underwent ovariectomy and were randomized to undergo implantation with subcutaneous 21-day sustained release pellets containing progesterone 50 mg (n = 22) or placebo (n = 23). After 20 days, hearts were excised, mounted, and perfused with modified Krebs-Henseleit solution. The atrioventricular (AV) node was destroyed manually. Following a 15-minute equilibration period, hearts were perfused with dofetilide 100 nM for 30 minutes, during which the electrocardiogram was recorded continuously. Incidences of spontaneous TdP, other ventricular arrhythmias and mean QTc intervals were compared. Median serum progesterone concentrations were higher in progesterone vs placebo-treated rabbits (3.8 [range, 2.8-5.1] vs 0.7 [0.4-1.7] ng/mL, P < 0.0001). Median serum estradiol concentrations were similar (58 [22-72] vs 53 [34-62] pg/mL), P = 0.79). The incidence of TdP was lower in hearts from progesterone-treated rabbits (27% vs 61%, P = 0.049). The incidences of bigeminy (36% vs 74%, P = 0.03) and trigeminy (18% vs 57%, P = 0.01) were also lower in hearts from progesterone-treated rabbits. There was no significant difference between groups in incidence of couplets (59% vs 74%, P = 0.54) or monomorphic ventricular tachycardia (14% vs 30%, P = 0.28). Maximum QT c interval and short-term beat-to-beat QT interval variability during dofetilide perfusion were significantly shorter in hearts from progesterone-treated rabbits. CONCLUSIONS Pretreatment with progesterone reduces the incidence of drug-induced TdP, bigeminy, and trigeminy in isolated perfused AV node-ablated rabbit hearts.
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Affiliation(s)
- James E Tisdale
- Department of Pharmacy Practice, College of Pharmacy, Purdue University, Indianapolis, Indiana.,Department of Medicine, School of Medicine, Indiana University, Indianapolis, Indiana
| | - Heather A Jaynes
- Department of Pharmacy Practice, College of Pharmacy, Purdue University, Indianapolis, Indiana
| | - Brian R Overholser
- Department of Pharmacy Practice, College of Pharmacy, Purdue University, Indianapolis, Indiana.,Department of Medicine, School of Medicine, Indiana University, Indianapolis, Indiana
| | - Kevin M Sowinski
- Department of Pharmacy Practice, College of Pharmacy, Purdue University, Indianapolis, Indiana.,Department of Medicine, School of Medicine, Indiana University, Indianapolis, Indiana
| | - Richard J Kovacs
- Department of Medicine, Krannert Institute of Cardiology, School of Medicine, Indiana University, Indianapolis, Indiana
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Ko EYJ, Carpenter CM, Gagnon DJ, Andrle AM. Pharmacist-Managed Inpatient Dofetilide Initiation Program: Description and Adherence Rate Post-Root Cause Analysis. J Pharm Pract 2019; 33:784-789. [PMID: 30935279 DOI: 10.1177/0897190019834130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this article is to describe the pharmacist-managed dofetilide initiation program at Maine Medical Center (MMC), assess the adherence rate to 8 core clinical metrics, and review adverse effects before and after a root cause analysis (RCA). Core clinical metrics included pharmacist note entered within 4 hours of dose administration, dose chosen correctly per renal function, QTc measurements obtained and reviewed 2 hours after each dose, appropriate dose adjustment per the most recent QTc measurement, documentation of patient education, and assessment of conduction abnormality, drug-drug interactions, and serum potassium and magnesium concentrations. The primary outcome was adherence rate to all 8 core clinical metrics before and after the RCA. The safety outcome was the total number of adverse events. One hundred patients undergoing elective dofetilide initiation were evaluated: 50 pre-RCA and 50 post-RCA. Adherence rate to all core metrics was 14% in the pre-RCA group and 44% in the post-RCA group (P < .001). Torsade de pointes occurred 3 times in the pre-RCA group and never in the post-RCA group. After the RCA, adherence to MMC's pharmacist-managed inpatient dofetilide initiation program significantly improved.
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Affiliation(s)
| | - Charles M Carpenter
- Department of Cardiology, Maine Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - David J Gagnon
- Department of Pharmacy Practice, Maine Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Anne M Andrle
- Department of Pharmacy Practice, Maine Medical Center, Portland, ME, USA
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22
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Carstensen H, Hesselkilde EZ, Haugaard MM, Flethøj M, Carlson J, Pehrson S, Jespersen T, Platonov PG, Buhl R. Effects of dofetilide and ranolazine on atrial fibrillatory rate in a horse model of acutely induced atrial fibrillation. J Cardiovasc Electrophysiol 2019; 30:596-606. [PMID: 30661267 PMCID: PMC6849868 DOI: 10.1111/jce.13849] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 12/21/2018] [Accepted: 01/04/2019] [Indexed: 12/19/2022]
Abstract
INTRODUCTION The atrial fibrillatory rate is a potential biomarker in the study of antiarrhythmic drug effects on atrial fibrillation (AF). The purpose of this study was to evaluate whether dose-dependent changes in the atrial fibrillatory rate can be monitored on surface electrocardiography (ECG) following treatment with dofetilide, ranolazine, and a combination of the two in an acute model of AF in horses. METHODS AND RESULTS Eight horses were subjected to pacing-induced AF on 4 separate days. Saline (control), dofetilide, ranolazine, or a combination of dofetilide and ranolazine was administered in four incremental doses. Atrial fibrillatory activity was extracted from surface ECGs using spatiotemporal QRST cancellation. The mean atrial fibrillatory rate before drug infusion was 297 ± 27 fpm. Dofetilide reduced the atrial fibrillatory rate following the infusion of low doses (0.89 µg/kg, P < 0.05) and within 5 minutes preceding cardioversion (P < 0.05). Cardioversion with ranolazine was preceded by a reduction in the atrial fibrillatory rate in the last minute (P < 0.05). The combination of drugs reduced the atrial fibrillatory rate in a similar manner to dofetilide used alone. A trend toward a lower atrial fibrillatory rate before drug infusion was found among horses cardioverting on low doses of the drugs. CONCLUSION The atrial fibrillatory rate derived from surface ECGs showed a difference in the mode of action on AF between dofetilide and ranolazine. Dofetilide reduced the atrial fibrillatory rate, whereas ranolazine displayed a cardioverting mechanism that was distinct from a slowing of the fibrillatory process.
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Affiliation(s)
- Helena Carstensen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Eva Zander Hesselkilde
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Maria Mathilde Haugaard
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Mette Flethøj
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Jonas Carlson
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Steen Pehrson
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Taastrup, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
| | - Pyotr G Platonov
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden.,Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden
| | - Rikke Buhl
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
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23
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Biktarvy--another INSTI-based combination for HIV. Med Lett Drugs Ther 2018; 60:132-5. [PMID: 30133424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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24
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Abstract
An 84-year-old woman presented to her primary care physician with an unexplained 4-month history of weight and appetite loss after initiation of dofetilide 125 mcg orally twice daily for atrial fibrillation. She was noted to have lost 2.5 kg, which was a 3.6% decrease from her initial body weight of 69.4 kg. After excluding other etiologies for her anorexia, such as medication changes or changes in other diseases or conditions, her primary care physician and cardiologists elected to continue dofetilide but monitor the patient's appetite and body weight. After 7 months of dofetilide use with persistent appetite loss, the cardiology team discontinued dofetilide. Continued weight loss was observed until approximately 1 month after stopping dofetilide, with a maximum weight loss of 2.9 kg or a 4.2% decrease. Improvements in appetite were reported 2 months after discontinuing dofetilide, with minor increases in weight that eventually stabilized. In this case, while taking dofetilide, the patient experienced anorexia leading to weight loss that subsided after discontinuation of the drug. Based on the temporal association between the patient's changes in appetite and body weight and treatment with dofetilide, the drug was most likely the cause of the patient's anorexia. We are unaware of other reports of anorexia associated with dofetilide, but clinicians may want to consider the drug as a potential cause for otherwise unexplained changes in appetite or body weight.
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Affiliation(s)
- Jerald V Felipe
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
| | - Danielle R Fixen
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
| | - Sunny A Linnebur
- Department of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 E. Montview Blvd (C238), Aurora, CO 80045, USA
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25
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Cho JH, Youn SJ, Moore JC, Kyriakakis R, Vekstein C, Militello M, Poe SM, Wolski K, Tchou PJ, Varma N, Niebauer MJ, Bhargava M, Saliba WI, Wazni OM, Lindsay BD, Wilkoff BL, Chung MK. Safety of Oral Dofetilide Reloading for Treatment of Atrial Arrhythmias. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.005333. [PMID: 29038104 DOI: 10.1161/circep.117.005333] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 08/23/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Although dofetilide labeling states that the drug must be initiated or reinitiated with continuous electrocardiographic monitoring and in the presence of trained personnel, the risks of dofetilide reloading justifying repeat hospitalization have not been investigated. METHODS AND RESULTS Patients admitted for dofetilide reloading for atrial arrhythmias were retrospectively reviewed. The need for dose adjustment and the incidence of torsades de pointes (TdP) were identified. The incidence of TdP in dofetilide reloading was compared with patients admitted for dofetilide initial loading. Of 138 patients admitted for dofetilide reloading for atrial arrhythmias, 102 were reloaded at a previously tolerated dose, 30 with a higher dose from a previously tolerated dose and 2 at a lower dose; prior dosage was unknown in 4 patients. Dose adjustment or discontinuation was required in 44 patients (31.9%). No TdP occurred in the same dose reloading group, but TdP occurred in 2 patients admitted to increase dofetilide dosage (0% versus 6.7%; P=0.050). Dofetilide dose adjustment or discontinuation was required in 30 of 102 patients (29.4%) reloaded at a previously tolerated dose and in 11 of 30 patients (36.7%) admitted for an increase in dose. CONCLUSIONS Although no TdP occurred in patients admitted to reload dofetilide at the same dose as previously tolerated, dosage adjustments or discontinuation was frequent and support the need for hospitalization for dofetilide reloading. Patients admitted for reloading with a higher dose tended to be at higher risk for TdP than patients reloaded at a prior tolerated dose.
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Affiliation(s)
- Jae Hyung Cho
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - So Jin Youn
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - JoEllyn C Moore
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Roxanne Kyriakakis
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Carolyn Vekstein
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Michael Militello
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Stacy M Poe
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Kathy Wolski
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Patrick J Tchou
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Niraj Varma
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Mark J Niebauer
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Mandeep Bhargava
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Walid I Saliba
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Oussama M Wazni
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Bruce D Lindsay
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Bruce L Wilkoff
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH
| | - Mina K Chung
- From the Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH. Current address for Dr Cho: Cedars-Sinai Heart Institute, Los Angeles, CA. Current address for Dr Youn: Department of Internal Medicine, Cleveland Clinic, OH. Current address for Dr Moore: Minneapolis Heart Institute, Abbott Northwestern Hospital, MN. Current address for R. Kyriakakis: College of Medicine, Medical University of South Carolina, Charleston. Current address for C. Vekstein: Dana-Farber Cancer Institute, Boston, MA. Current address for M. Militello: Pharmacy Department, Cleveland Clinic, OH.
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Briceño DF, Supple GE. Dofetilide Reloaded: To Admit or Not to Admit, That is the Question. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.005815. [PMID: 29038110 DOI: 10.1161/circep.117.005815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 09/16/2017] [Indexed: 11/16/2022]
Affiliation(s)
- David F Briceño
- From the Electrophysiology Section, Cardiology Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia
| | - Gregory E Supple
- From the Electrophysiology Section, Cardiology Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia.
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Britton OJ, Abi-Gerges N, Page G, Ghetti A, Miller PE, Rodriguez B. Quantitative Comparison of Effects of Dofetilide, Sotalol, Quinidine, and Verapamil between Human Ex vivo Trabeculae and In silico Ventricular Models Incorporating Inter-Individual Action Potential Variability. Front Physiol 2017; 8:597. [PMID: 28868038 PMCID: PMC5563361 DOI: 10.3389/fphys.2017.00597] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/02/2017] [Indexed: 01/20/2023] Open
Abstract
Background:In silico modeling could soon become a mainstream method of pro-arrhythmic risk assessment in drug development. However, a lack of human-specific data and appropriate modeling techniques has previously prevented quantitative comparison of drug effects between in silico models and recordings from human cardiac preparations. Here, we directly compare changes in repolarization biomarkers caused by dofetilide, dl-sotalol, quinidine, and verapamil, between in silico populations of human ventricular cell models and ex vivo human ventricular trabeculae. Methods and Results:Ex vivo recordings from human ventricular trabeculae in control conditions were used to develop populations of in silico human ventricular cell models that integrated intra- and inter-individual variability in action potential (AP) biomarker values. Models were based on the O'Hara-Rudy ventricular cardiomyocyte model, but integrated experimental AP variability through variation in underlying ionic conductances. Changes to AP duration, triangulation and early after-depolarization occurrence from application of the four drugs at multiple concentrations and pacing frequencies were compared between simulations and experiments. To assess the impact of variability in IC50 measurements, and the effects of including state-dependent drug binding dynamics, each drug simulation was repeated with two different IC50 datasets, and with both the original O'Hara-Rudy hERG model and a recently published state-dependent model of hERG and hERG block. For the selective hERG blockers dofetilide and sotalol, simulation predictions of AP prolongation and repolarization abnormality occurrence showed overall good agreement with experiments. However, for multichannel blockers quinidine and verapamil, simulations were not in agreement with experiments across all IC50 datasets and IKr block models tested. Quinidine simulations resulted in overprolonged APs and high incidence of repolarization abnormalities, which were not observed in experiments. Verapamil simulations showed substantial AP prolongation while experiments showed mild AP shortening. Conclusions: Results for dofetilide and sotalol show good agreement between experiments and simulations for selective compounds, however lack of agreement from simulations of quinidine and verapamil suggest further work is needed to understand the more complex electrophysiological effects of these multichannel blocking drugs.
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Affiliation(s)
- Oliver J. Britton
- Department of Computer Science, University of OxfordOxford, United Kingdom
| | | | - Guy Page
- AnaBios CorporationSan Diego, CA, United States
| | | | | | - Blanca Rodriguez
- Department of Computer Science, University of OxfordOxford, United Kingdom
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VanderLugt JT, Bon C, Knuth D, Schreiber R, Ruff MD. Pharmacokinetics and Bioequivalence of Branded and Generic Formulations of Dofetilide 0.5-mg Capsules After Single-Dose Administration in Healthy Subjects. Clin Pharmacol Drug Dev 2017; 7:311-318. [PMID: 28800211 DOI: 10.1002/cpdd.371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/23/2017] [Indexed: 11/10/2022]
Abstract
Class III antiarrhythmics are preferred therapy for managing atrial fibrillation/flutter. Dofetilide 0.5-mg capsules were US Food and Drug Administration (FDA) approved in 1999 to treat atrial fibrillation/flutter. Bioequivalence of generic dofetilide is important for treating arrhythmias because drug concentrations must be consistent to maintain normal sinus rhythm. Generic dofetilide 0.5-mg capsule pharmacokinetics were compared with branded product in 2 open-label, 2-way crossover, single-dose studies - 1 study each in fasted and fed healthy subjects. Blood samples were collected before and up to 48 hours after dosing. Safety was assessed by tabulating adverse events and vital signs. Seventy-three subjects were enrolled; 59 completed the studies. In fasted subjects, the 90% confidence intervals (CIs) for generic dofetilide 0.5 mg versus the reference formulation were 0.996-1.026 for the area under the plasma concentration-time curve from 0 to infinity (AUC) and 0.974-1.066 for the maximum observed concentration (Cmax ). In fed subjects, the 90%CIs for AUC and Cmax were 0.988-1.015 and 0.928-0.992, respectively. All ratios were within the FDA-established bioequivalence range. Twenty-six subjects experienced 37 adverse events (generic, 15; reference, 22); all but 1 were mild or moderate in severity. Generic dofetilide 0.5-mg capsules can be considered bioequivalent to the reference product.
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Affiliation(s)
| | - Charles Bon
- Biostudy Solutions, LLC, Wilmington, NC, USA
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Yang PC, Perissinotti LL, López-Redondo F, Wang Y, DeMarco KR, Jeng MT, Vorobyov I, Harvey RD, Kurokawa J, Noskov SY, Clancy CE. A multiscale computational modelling approach predicts mechanisms of female sex risk in the setting of arousal-induced arrhythmias. J Physiol 2017; 595:4695-4723. [PMID: 28516454 PMCID: PMC5509858 DOI: 10.1113/jp273142] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/24/2017] [Indexed: 01/10/2023] Open
Abstract
KEY POINTS This study represents a first step toward predicting mechanisms of sex-based arrhythmias that may lead to important developments in risk stratification and may inform future drug design and screening. We undertook simulations to reveal the conditions (i.e. pacing, drugs, sympathetic stimulation) required for triggering and sustaining reentrant arrhythmias. Using the recently solved cryo-EM structure for the Eag-family channel as a template, we revealed potential interactions of oestrogen with the pore loop hERG mutation (G604S). Molecular models suggest that oestrogen and dofetilide blockade can concur simultaneously in the hERG channel pore. ABSTRACT Female sex is a risk factor for inherited and acquired long-QT associated torsade de pointes (TdP) arrhythmias, and sympathetic discharge is a major factor in triggering TdP in female long-QT syndrome patients. We used a combined experimental and computational approach to predict 'the perfect storm' of hormone concentration, IKr block and sympathetic stimulation that induces arrhythmia in females with inherited and acquired long-QT. More specifically, we developed mathematical models of acquired and inherited long-QT syndrome in male and female ventricular human myocytes by combining effects of a hormone and a hERG blocker, dofetilide, or hERG mutations. These 'male' and 'female' model myocytes and tissues then were used to predict how various sex-based differences underlie arrhythmia risk in the setting of acute sympathetic nervous system discharge. The model predicted increased risk for arrhythmia in females when acute sympathetic nervous system discharge was applied in the settings of both inherited and acquired long-QT syndrome. Females were predicted to have protection from arrhythmia induction when progesterone is high. Males were protected by the presence of testosterone. Structural modelling points towards two plausible and distinct mechanisms of oestrogen action enhancing torsadogenic effects: oestradiol interaction with hERG mutations in the pore loop containing G604 or with common TdP-related blockers in the intra-cavity binding site. Our study presents findings that constitute the first evidence linking structure to function mechanisms underlying female dominance of arousal-induced arrhythmias.
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Affiliation(s)
- Pei-Chi Yang
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Laura L Perissinotti
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Fernando López-Redondo
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University
| | - Yibo Wang
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Kevin R DeMarco
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Mao-Tsuen Jeng
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Igor Vorobyov
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno, NV, USA
| | - Junko Kurokawa
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University.,Department of Bio-informational Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Sergei Y Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Alberta, Canada
| | - Colleen E Clancy
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
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30
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Abstract
Background Although atrial fibrillation (AF) is the most common abnormal heart rhythm and its prevalence continues to rise, there is a marked paucity of effective and safe antiarrhythmic drugs for AF. This study was done to test whether combined use of dofetilide and mexiletine exhibits not only a synergistic effect on AF suppression but also a safer profile in drug‐induced ventricular proarrhythmias. Methods and Results The effects of dofetilide plus mexiletine on atrial effective refractory period (ERP), AF inducibility, QT, and QT‐related ventricular arrhythmias were studied using the isolated arterially perfused rabbit atrial and ventricular wedge preparations. Dofetilide or mexiletine alone mildly to moderately prolonged atrial ERP, but their combined use produced a markedly rate‐dependent increase in atrial ERP. Dofetilide (3 nmol/L) plus mexiletine (10 μmol/L) increased the ERP by 28.2% from 72.2±5.7 to 92.8±5.9 ms (n=9, P<0.01) at a pacing rate of 0.5 Hz and by 94.5% from 91.7±5.2 to 178.3±12.0 ms (n=9, P<0.01) at 3.3 Hz. Dofetilide plus mexiletine strongly suppressed AF inducibility. On the other hand, dofetilide at 10 nmol/L produced marked QT and Tp‐e prolongation, steeper QT‐BCL and Tp‐e‐BCL slopes, and induced early afterdepolarizations and torsade de pointes in the ventricular wedges. Mexiletine at 10 μmol/L reduced dofetilide‐induced QT and Tp‐e prolongation, QT‐BCL and Tp‐e‐BCL slopes, and abolished early afterdepolarizations and torsade de pointes. Conclusions In rabbits, combined use of dofetilide and mexiletine not only synergistically increases atrial ERP and effectively suppresses AF inducibility, but also markedly reduces QT liability and torsade de pointes risk posed by dofetilide alone.
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Affiliation(s)
- Guizhi Liu
- First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaolin Xue
- Department of Cardiology, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Chuanyu Gao
- Department of Cardiology, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Jiaqi Huang
- Lankenau Institute for Medical Research, Wynnewood, PA
| | - Datun Qi
- Department of Cardiology, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Yanzhou Zhang
- First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jian-Zeng Dong
- First Affiliated Hospital of Zhengzhou University, Zhengzhou, China .,Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Chang-Sheng Ma
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Gan-Xin Yan
- Department of Cardiology, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China .,Lankenau Institute for Medical Research, Wynnewood, PA.,Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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31
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Cohen IS, Lin RZ, Ballou LM. Acquired long QT syndrome and phosphoinositide 3-kinase. Trends Cardiovasc Med 2017; 27:451-459. [PMID: 28687226 DOI: 10.1016/j.tcm.2017.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 01/08/2023]
Abstract
While it is well known that mutation of several different ion channels can cause congenital long QT syndrome, block of IKr is widely thought to be responsible for most cases of drug-induced acquired long QT syndrome (aLQTS). In this article, we review evidence supporting another cause of aLQTS due to inhibition of phosphoinositide 3-kinase (PI3K) signaling. Inhibition of PI3K affects multiple plateau currents, reducing IKr, IKs, and ICaL while increasing the persistent sodium current (INaP). The effects of PI3K inhibitors develop slowly, requiring hours to days to reach steady state. Dofetilide and terfenadine, an antihistamine on which much of the original IKr hypothesis was based, are among the many drugs that inhibit the PI3K pathway. Reduced PI3K signaling may also play a role in aLQTS associated with diabetes. Drug safety testing to identify aLQTS risk may be improved by examining PI3K-dependent effects that develop over time.
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Affiliation(s)
- Ira S Cohen
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY.
| | - Richard Z Lin
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY; Medical Service, Northport VA Medical Center, Northport, NY
| | - Lisa M Ballou
- Department of Physiology and Biophysics, The Institute for Molecular Cardiology, Stony Brook University, Stony Brook, NY
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Singh SM, D'Avila A, Aryana A, Kim YH, Mangrum JM, Michaud GF, Dukkipati SR, Heist EK, Barrett CD, Thorpe KE, Reddy VY. Persistent Atrial Fibrillation Ablation in Females: Insight from the MAGIC-AF Trial. J Cardiovasc Electrophysiol 2016; 27:1259-1263. [PMID: 27461576 DOI: 10.1111/jce.13051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 07/07/2016] [Accepted: 07/15/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Atrial fibrillation (AF) ablation is less frequently performed in women when compared to men. There are conflicting data on the safety and efficacy of AF ablation in women. The objective of this study was to compare the clinical characteristics and outcomes in a contemporary cohort of men and women undergoing persistent AF ablation procedures. METHODS AND RESULTS A total of 182 men and 53 women undergoing a first-ever persistent AF catheter ablation procedure in The Modified Ablation Guided by Ibutilide Use in Chronic Atrial Fibrillation (MAGIC-AF) trial were evaluated. Clinical and procedural characteristics were compared between each gender. The primary efficacy endpoint was the 1-year single procedure freedom from atrial arrhythmia off anti-arrhythmic drugs. Women undergoing catheter ablation procedures were older than men (P < 0.001). The duration of AF and associated co-morbidities were similar between both genders. Single procedure drug-free atrial arrhythmia recurrence occurred in 53% of the cohort with no difference based on gender (men = 54%, women = 53%; P = 1.0). Procedural (P = 0.04), fluoroscopic (P = 0.02), and ablation times (P = 0.003) were shorter in women compared to men. Periprocedural complications and postablation improvement in quality of life were similar between men and women. CONCLUSION Women undergoing a first-ever persistent AF ablation procedure were older but had similar clinical outcomes and complications when compared with men.
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Affiliation(s)
- Sheldon M Singh
- Schulich Heart Program, Sunnybrook Health Science Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Andre D'Avila
- Helmsley Cardiac Arrhythmia Service, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Instituto de Pesquisa em Arritmia Cardiaca - Hospital Cardiologico, Florianopolis, SC, Brazil
| | - Arash Aryana
- Mercy General Hospital and Dignity Health Heart & Vascular Institute, Sacramento, California, USA
| | - Young-Hoon Kim
- Cardiovascular Division, Korea University Medical Center, Seoul, Korea
| | - J Michael Mangrum
- Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia
| | - Gregory F Michaud
- Cardiovascular Division, Brigham and Women's Hospital, Harvard University, Boston, Massachusetts
| | - Srinivas R Dukkipati
- Helmsley Cardiac Arrhythmia Service, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - E Kevin Heist
- Heart Center, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Conor D Barrett
- Heart Center, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Kevin E Thorpe
- Dalla Lana School of Public Health, Keenan Research Centre, Li Ka Shing Knowledge Institute of St. Michael's Hospital University of Toronto, Toronto, Canada
| | - Vivek Y Reddy
- Helmsley Cardiac Arrhythmia Service, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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33
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Stavrakis S, Dyer JW, Koomson E, Scherlag BJ, Bhardwaj B, Lazzara R, Po SS. Spectral Analysis of Baseline Electrocardiogram During Atrial Fibrillation Predicts Response to Antiarrhythmic Drug Therapy in Patients With Persistent Atrial Fibrillation. J Cardiovasc Electrophysiol 2016; 27:1312-1318. [PMID: 27506321 DOI: 10.1111/jce.13064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/28/2016] [Accepted: 08/02/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND We evaluated the ability of spectral analysis of the baseline ECG during atrial fibrillation (AF) to predict the response of persistent AF to antiarrhythmic drug therapy. METHODS Patients with persistent AF who were admitted for dofetilide loading were prospectively enrolled in the study. Atrial activity was extracted from the ECG using an Independent Component Analysis method and then subjected to a Modified Periodogram. The regularity index was computed as the ratio of the power in the dominant frequency and all its harmonics to the total power in the spectrum. Patients were followed at 1 month, 3 months and every 3 months thereafter. RESULTS Of 28 patients enrolled in the study, 14 (50%) converted acutely to sinus rhythm during the 3-day hospital loading period. The clinical and echocardiographic characteristics of patients with and without acute pharmacologic conversion were similar. The regularity index was significantly higher in those who converted to sinus rhythm compared to those who did not (0.71 ± 0.20 vs. 0.38 ± 0.13, respectively; P < 0.0001). A regularity index ≥0.44 had a 79% sensitivity and 93% specificity to predict acute conversion and was associated with a nearly 5-fold increase in the acute conversion rate (odds ratio = 4.89; 95% confidence interval 1.74-13.75; P = 0.003). The regularity index was the only independent predictor of acute conversion. Neither acute conversion, nor the regularity index predicted sinus rhythm maintenance, after a median follow-up of 10 months. CONCLUSION Increased regularity index predicts acute conversion of persistent AF during dofetilide loading, but does not predict long-term sinus rhythm maintenance.
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Affiliation(s)
- Stavros Stavrakis
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - John W Dyer
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Edward Koomson
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Benjamin J Scherlag
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Bhaskar Bhardwaj
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Ralph Lazzara
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Sunny S Po
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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34
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Qiu XS, Chauveau S, Anyukhovsky EP, Rahim T, Jiang YP, Harleton E, Feinmark SJ, Lin RZ, Coronel R, Janse MJ, Opthof T, Rosen TS, Cohen IS, Rosen MR. Increased Late Sodium Current Contributes to the Electrophysiological Effects of Chronic, but Not Acute, Dofetilide Administration. Circ Arrhythm Electrophysiol 2016; 9:e003655. [PMID: 27071826 DOI: 10.1161/circep.115.003655] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 03/01/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Drugs are screened for delayed rectifier potassium current (IKr) blockade to predict long QT syndrome prolongation and arrhythmogenesis. However, single-cell studies have shown that chronic (hours) exposure to some IKr blockers (eg, dofetilide) prolongs repolarization additionally by increasing late sodium current (INa-L) via inhibition of phosphoinositide 3-kinase. We hypothesized that chronic dofetilide administration to intact dogs prolongs repolarization by blocking IKr and increasing INa-L. METHODS AND RESULTS We continuously infused dofetilide (6-9 μg/kg bolus+6-9 μg/kg per hour IV infusion) into anesthetized dogs for 7 hours, maintaining plasma levels within the therapeutic range. In separate experiments, myocardial biopsies were taken before and during 6-hour intravenous dofetide infusion, and the level of phospho-Akt was determined. Acute and chronic dofetilide effects on action potential duration (APD) were studied in canine left ventricular subendocardial slabs using microelectrode techniques. Dofetilide monotonically increased QTc and APD throughout 6.5-hour exposure. Dofetilide infusion during ≥210 minutes inhibited Akt phosphorylation. INa-L block with lidocaine shortened QTc and APD more at 6.5 hours than at 50 minutes (QTc) or 30 minutes (APD) dofetilide administration. In comparison, moxifloxacin, an IKr blocker with no effects on phosphoinositide 3-kinase and INa-L prolonged APD acutely but no additional prolongation occurred on chronic superfusion. Lidocaine shortened APD equally during acute and chronic moxifloxacin superfusion. CONCLUSIONS Increased INa-L contributes to chronic dofetilide effects in vivo. These data emphasize the need to include time and INa-L in evaluating the phosphoinositide 3-kinase inhibition-derived proarrhythmic potential of drugs and provide a mechanism for benefit from lidocaine administration in clinical acquired long QT syndrome.
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Affiliation(s)
- Xiaoliang S Qiu
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Samuel Chauveau
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Evgeny P Anyukhovsky
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Tania Rahim
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Ya-Ping Jiang
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Erin Harleton
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Steven J Feinmark
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Richard Z Lin
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Ruben Coronel
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Michiel J Janse
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Tobias Opthof
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Tove S Rosen
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
| | - Ira S Cohen
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.).
| | - Michael R Rosen
- From the Department of Physiology and Biophysics, Stony Brook University, NY (X.S.Q., S.C., E.P.A., T.R., Y.-P.J., R.Z.L., I.S.C.); Departments of Pharmacology (E.H., S.J.F., M.R.R.) and Pediatrics (T.S.R., M.R.R.), College of Physician and Surgeons of Columbia University, New York, NY; Medical Service, Northport VA Medical Center, NY (R.Z.L.); Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands (R.C., M.J.J., T.O.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Department of Medical Physiology, University Medical Center Utrecht, The Netherlands (T.O.)
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Anand V, Vakil K, Tholakanahalli V, Li JM, McFalls E, Adabag S. Discontinuation of Dofetilide From QT Prolongation and Ventricular Tachycardia in the Real World. JACC Clin Electrophysiol 2016; 2:777-781. [PMID: 29759759 DOI: 10.1016/j.jacep.2016.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/26/2016] [Accepted: 05/12/2016] [Indexed: 01/31/2023]
Abstract
OBJECTIVES The purpose of this study was to determine the incidence and correlates of QT prolongation or ventricular tachycardia (VT) resulting in discontinuation of dofetilide in a real-world setting. BACKGROUND Dofetilide is a class III antiarrhythmic agent approved for achieving and maintaining sinus rhythm in patients with symptomatic atrial fibrillation. Because of a risk of QT prolongation and VT, patients starting dofetilide need to be hospitalized for 3 days to closely monitor telemetry and electrocardiography. In large clinical trials, <3% of patients had to discontinue dofetilide because of QT prolongation, but data from real-world experience are lacking. METHODS We examined 114 consecutive patients with atrial fibrillation who were hospitalized for starting dofetilide at the Minneapolis Veterans Affairs Health Care System from 2011 to 2014. RESULTS The mean age of the patients was 64 ± 8 years. Dofetilide was discontinued in 22 (19%) patients because of QT prolongation (17%) or VT (2%). A total of 32 (28%) patients were taking other QT-prolonging drugs. Of these, 10 (31%) had to discontinue dofetilide versus 12 (15%) of the 82 patients who were not taking any other QT-prolonging drugs (p = 0.04). Patients who were taking concomitant QT-prolonging drugs were 1.9 times more likely to discontinue dofetilide (95% confidence interval: 1.1 to 3.4; p = 0.04) compared with those who were not taking any other QT-prolonging drugs. CONCLUSIONS The incidence of QT prolongation or VT that lead to discontinuation of dofetilide is remarkably higher in the real-world setting than in clinical trials. Concomitant use of other QT-prolonging drugs was associated with discontinuation of dofetilide.
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Affiliation(s)
- Vidhu Anand
- Division of Cardiology, Veterans Affairs Health Care System, Minneapolis, Minnesota; Department of Medicine, Division of Cardiology, University of Minnesota, Minneapolis, Minnesota
| | - Kairav Vakil
- Division of Cardiology, Veterans Affairs Health Care System, Minneapolis, Minnesota; Department of Medicine, Division of Cardiology, University of Minnesota, Minneapolis, Minnesota
| | - Venkatakrishna Tholakanahalli
- Division of Cardiology, Veterans Affairs Health Care System, Minneapolis, Minnesota; Department of Medicine, Division of Cardiology, University of Minnesota, Minneapolis, Minnesota
| | - Jian-Ming Li
- Division of Cardiology, Veterans Affairs Health Care System, Minneapolis, Minnesota; Department of Medicine, Division of Cardiology, University of Minnesota, Minneapolis, Minnesota
| | - Edward McFalls
- Division of Cardiology, Veterans Affairs Health Care System, Minneapolis, Minnesota; Department of Medicine, Division of Cardiology, University of Minnesota, Minneapolis, Minnesota
| | - Selcuk Adabag
- Division of Cardiology, Veterans Affairs Health Care System, Minneapolis, Minnesota; Department of Medicine, Division of Cardiology, University of Minnesota, Minneapolis, Minnesota.
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Gillette MA, Shah BM, Schafer JJ, DeSimone JA. Dolutegravir: a new integrase strand transfer inhibitor for the treatment of HIV - an alternative viewpoint. Pharmacotherapy 2015; 34:e173-4. [PMID: 25182330 DOI: 10.1002/phar.1478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Michael A Gillette
- Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas
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Raygor VP, Ng J, Goldberger JJ. Surface ECG f Wave Analysis of Dofetilide Drug Effect in the Atrium. J Cardiovasc Electrophysiol 2015; 26:644-8. [PMID: 25711372 DOI: 10.1111/jce.12645] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 02/05/2015] [Accepted: 02/20/2015] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The electrocardiogram (ECG) fibrillatory (f) wave characteristics in atrial fibrillation (AF) could provide important information regarding the efficacy of antiarrhythmic drug therapy. METHODS AND RESULTS To measure the effects of dofetilide on the surface ECG f wave characteristics in patients with persistent AF, baseline and post-drug (2 hours after first dose and after multiple doses) ECGs in 31 patients with persistent AF admitted for dofetilide loading were evaluated. A QRST template subtraction algorithm was used to yield an atrial ECG. Fast Fourier transform analysis was performed to evaluate the maximum organizational index (OI), the dominant frequency (DF) in the lead with max OI, the median DF for all leads, and the vector magnitude f wave amplitude. Dofetilide reduced DF in the lead with the max OI (6.32 ± 0.98 Hz at baseline vs. 4.83 ± 0.63 Hz after final dose, P < 0.0001) and median DF (6.46 ± 0.87 Hz vs. 4.92 ± 0.62 Hz, P < 0.0001). Dofetilide also increased the maximum OI from 0.52 ± 0.11 at baseline to 0.59 ± 0.11 after final dose (P = 0.02). Of the 29 patients with long-term follow-up, the 22 (76%) with recurrent AF on dofetilide had a lower baseline DF in the lead with the max OI (6.01 ± 1.08 vs. 6.89 ± 0.46; P = 0.05). The change in DF after dofetilide did not correlate with the change in QTc interval. CONCLUSIONS The standard ECG can be used to assess atrial rate in AF. This may be useful to assess antiarrhythmic drug effects for treatment of AF.
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Affiliation(s)
- Viraj P Raygor
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Jason Ng
- Center for Cardiovascular Innovation and the Division of Cardiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Jeffrey J Goldberger
- Center for Cardiovascular Innovation and the Division of Cardiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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Agusala K, Oesterle A, Kulkarni C, Caprio T, Subacius H, Passman R. Risk prediction for adverse events during initiation of sotalol and dofetilide for the treatment of atrial fibrillation. Pacing Clin Electrophysiol 2015; 38:490-8. [PMID: 25626340 DOI: 10.1111/pace.12586] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 11/24/2014] [Accepted: 12/21/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Inpatient antiarrhythmic drug initiation for atrial fibrillation is mandated for dofetilide (DF) and is often performed for sotalol (SL), particularly if proarrhythmia risk factors are present. Whether low-risk patients can be identified to safely allow outpatient initiation is unknown. METHODS A single-center retrospective cohort study was performed on patients initiated with DF or SL. Risk factors for adverse events (AEs), defined as any arrhythmia or electrocardiogram change requiring dose reduction or cessation, were identified. RESULTS Of 329 patients, 227 (69%) received SL and 102 (31%) DF. The cohort had a mean age of 63 ± 13 years; 70% of patients were male and had a baseline QTc of 440 ± 37 ms. A total of 105 AEs occurred in 92 patients: QTc prolongation or ventricular tachyarrhythmia in 70 patients (67% of AEs), bradyarrhythmias in 35 patients (33% of AEs), with some experiencing both AE types. Ventricular arrhythmias were seen in 23 patients (7%) and torsades de pointes in one (0.3%). Total AE rates were similar between drugs (P = 0.09); however, DF patients had more QTc prolongation or ventricular arrhythmias (P = 0.001). In SL patients, there were no predictors for QTc prolongation or ventricular proarrhythmia. In DF patients, higher baseline QTc interval (odds ratio = 1.64/25 ms, P = 0.01) was an independent predictor of QTc prolongation or ventricular proarrhythmias. For patients without proarrhythmia risk factors, overall AE rate was 26%. CONCLUSIONS In conclusion, AEs are common during DF and SL initiation but rarely severe in hospitalized inpatients. Baseline QTc predicts AEs for DF patients only and AE are common even in "low-risk" patients. These results support in-hospital drug initiation for all DF and SL patients.
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Affiliation(s)
- Kartik Agusala
- From Northwestern University, Feinberg School of Medicine, Chicago, Illinois
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Stams TRG, Bourgonje VJA, Beekman HDM, Schoenmakers M, van der Nagel R, Oosterhoff P, van Opstal JM, Vos MA. The electromechanical window is no better than QT prolongation to assess risk of Torsade de Pointes in the complete atrioventricular block model in dogs. Br J Pharmacol 2014; 171:714-22. [PMID: 24490860 DOI: 10.1111/bph.12483] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 10/11/2013] [Accepted: 10/20/2013] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE The electromechanical window (EMW), the interval between the end of the T-wave and the end of the left ventricular pressure (LVP) curve, has recently been proposed as a predictor of risk of Torsade de Pointes (TdP) in healthy animals, whereby a negative EMW (mechanical relaxation earlier than repolarization) after drug administration indicates an increased TdP risk. The aims of this study were to assess (i) the effect of the ventricular remodelling in the canine chronic, complete atrioventricular block (CAVB) model on EMW; (ii) the effect of the I(Kr) -blocker dofetilide on EMW; and (iii) the correlation of EMW with TdP inducibility. EXPERIMENTAL APPROACH Our 11 year database of experiments of CAVB in dogs under general anaesthesia was reviewed and experiments included if ECG and LVP were recorded simultaneously at spontaneous rhythm. In total, 89 experiments in 44 dogs were appropriate and were analysed. KEY RESULTS During normally conducted sinus rhythm or acute atrioventricular block, EMW was positive. During CAVB, EMW was decreased to negative values. Dofetilide further reduced EMW before inducing repetitive TdP in 82% of the experiments. However, subclassification into inducible and non-inducible dogs revealed no difference in EMW. Analysis of the components of EMW revealed that the observed changes in EMW were solely caused by QT prolongation. CONCLUSIONS AND IMPLICATIONS In the canine CAVB model, ventricular remodelling and I(Kr) block by dofetilide are associated with negative EMW values, but this reflects QT prolongation, and implies that the EMW lacks specificity to predict dofetilide-induced TdP.
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Affiliation(s)
- T R G Stams
- Department of Medical Physiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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Osadchii OE. Impaired epicardial activation-repolarization coupling contributes to the proarrhythmic effects of hypokalaemia and dofetilide in guinea pig ventricles. Acta Physiol (Oxf) 2014; 211:48-60. [PMID: 24533513 DOI: 10.1111/apha.12259] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/09/2014] [Accepted: 02/10/2014] [Indexed: 11/30/2022]
Abstract
AIM Activation-repolarization coupling refers to the inverse relationship between action potential duration and activation time in myocardial regions along the path of ventricular excitation. This study examined whether the activation-repolarization coupling plays a role in coordinating repolarization times between the right ventricular (RV) and left ventricular (LV) chambers, and if impaired coordination contributes to electrical instability produced by hypokalaemia or dofetilide, a blocker of the delayed rectifier K(+) current. METHODS In Langendorff-perfused, isolated guinea pig hearts, six monophasic action potential recording electrodes were attached to RV and LV epicardium. Local activation time and action potential duration (APD90 ) were determined during spontaneous beating, regular pacing and extrasystolic excitation. RESULTS In regularly beating hearts, the RV epicardial sites had longer APD90 , but exhibited earlier activation times, as compared to LV sites, which minimized the interventricular difference in repolarization time. Upon extrasystolic stimulation, the APD90 was reduced to a greater extent in RV compared with LV, which translated to a reversed slope of APD90 -to-activation time relationship, and increased spatial repolarization gradients. Hypokalaemia and dofetilide prolonged APD90 , with the effect being greater in LV compared with RV. In hypokalaemic hearts, LV activation was delayed. These changes contributed to increased asynchrony in repolarization times in the LV and RV in both regular and extrasystolic beats, and enhanced susceptibility to tachyarrhythmia. CONCLUSION Impaired RV-to-LV activation-repolarization coupling is an important determinant of electrical instability in the setting of non-uniformly prolonged epicardial APD90 or slowed interventricular conduction.
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Affiliation(s)
- O. E. Osadchii
- Department of Biomedical Sciences; University of Copenhagen; Copenhagen N Denmark
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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Mosller M. Dofetilide in patients with left ventricular dysfunction and either heart failure or acute myocardial infarction: rationale, design, and patient characteristics of the DIAMOND studies. Danish Investigations of Arrhythmia and Mortality ON Dofetilide. Clin Cardiol 2009; 20:704-10. [PMID: 9259163 PMCID: PMC6656146 DOI: 10.1002/clc.4960200808] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Attempts to prolong life with antiarrhythmic drugs in patients at increased risk of sudden cardiac death have so far been disappointing or inconclusive. HYPOTHESIS The Danish Investigations of Arrhythmia and Mortality ON Dofetilide (DIAMOND) encompass two survival studies testing the prophylactic use of the selective potassium-channel blocker, dofetilide, in patients at high risk of sudden death. METHODS The first study includes patients admitted to hospital with congestive heart failure (CHF), the other includes patients with acute myocardial infarction (MI) within the previous 7 days. In both studies patients must have left ventricular systolic dysfunction (ejection fraction < or = 35%) determined by echocardiography. Each of the two studies are planned to enroll 1500 patients. Consecutive hospitalized patients with MI or CHF are screened in 37 Danish hospitals. Eligible patients are randomized to receive dofetilide or matching placebo. All patients are continuously monitored by telemetry for the first 3 days of the study to detect possible arrhythmic events and to ensure resuscitation in case of serious arrhythmias. Minimum duration of follow-up is 12 months. RESULTS Between November 1993 and July 1996, a total of 5812 consecutive patients with CHF and 8688 consecutive patients with MI was screened for entry. Of these, 1518 patients were included in the CHF study and 1510 patients in the MI study. Overall 1-year mortality of randomized patients were 28 and 22%, respectively. CONCLUSION DIAMOND will provide important data on the safety and efficacy of dofetilide in high-risk patients with left ventricular dysfunction and either CHF or MI, as well as evaluate tolerability in these populations.
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Abstract
BACKGROUND Although suppression of premature ventricular contractions (PVCs) is not a predictor of mortality over the long term, the extent of PVC suppression is an important characteristic of any antiarrhythmic drug. HYPOTHESIS This study was undertaken to determine whether intravenous (i.v.) dofetilide has the ability to suppress PVCs in patients who have frequent occurrences. METHODS Subjects were men and women, aged 18 to 75 years, with > 30 PVCs/h on two consecutive 24-h Holter recordings while drug free, and > 50 PVCs/h during a 2-hour telemetric electrocardiogram. The study was randomized, double-blind, and placebo controlled. Subjects received a single-blind, i.v. infusion of placebo and were randomized (3:1) to receive a double-blind second infusion of placebo or an infusion of dofetilide (a 15-min loading infusion of 4 g/kg followed by a 60-min maintenance infusion of 3.5 g/kg, for a total dose of 7.5 g/kg). RESULTS Dofetilide produced an 82.6% and placebo a 2.9% median reduction in PVCs. Drug responder rate, defined as 80% reduction in PVCs, was 50% in the dofetilide group and 0% in the placebo group. CONCLUSION Intravenous dofetilide significantly reduced PVCs in patients who had > 30 PVCs/h at baseline, and it produced > or = 80% reduction in PVCs in 50% of all subjects.
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Affiliation(s)
- P E Pool
- Reno Cardiology Research Laboratory, Nevada 89509, USA
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Haushalter TM, Friedrichs GS, Reynolds DL, Barecki-Roach M, Pastino G, Hayes R, Bass AS. The cardiovascular and pharmacokinetic profile of dofetilide in conscious telemetered beagle dogs and cynomolgus monkeys. Br J Pharmacol 2008; 154:1457-64. [PMID: 18604237 PMCID: PMC2492096 DOI: 10.1038/bjp.2008.275] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 06/03/2008] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE The effects of dofetilide were studied in monkeys and dogs. Pharmacokinetic data were generated together with the monitoring of cardiovascular changes in order to compare effects relative to human exposure. EXPERIMENTAL APPROACH Beagle dogs and cynomolgus monkeys were telemetered to collect arterial blood pressure, heart rate and ECG for 6 h after selected oral doses of dofetilide. Pharmacokinetic parameters were determined for each dose. KEY RESULTS Dogs: increases in the QT(c) interval reached 56 ms in dogs dosed with 0.3 mg kg(-1) of dofetilide. Premature ventricular contractions and right bundle branch block were evident at this dose, without changes in cardiovascular parameters. The mean C(max) values were 3.35 and 60.15 ng mL(-1) at doses of 0.03 and 0.3 mg kg(-1), respectively. Monkeys: increases in QT(c) intervals reached 40-50 ms after 0.03 mg kg(-1). T-wave changes were observed after 0.03 mg kg(-1) without changes in cardiovascular parameters. The mean C(max) values following oral doses of 0.01 and 0.03 mg kg(-1) were 0.919 ng mL(-1) and 1.85 ng mL(-1), respectively. CONCLUSIONS AND IMPLICATIONS Despite dofetilide exposure comparable to that in humans, QT(c) responses in dogs were greater than those reported in humans. A comparable human dose used in the monkey achieved only half of the exposure but was associated with twofold greater increases in QT(c). Our data support the view that safety risk assessments of new drugs in animal models should ensure that the clinical therapeutic range of exposure is achieved and any untoward effects interpreted accordingly.
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Affiliation(s)
- T M Haushalter
- Investigational and Regulatory Safety Pharmacology, Schering-Plough Research Institute, Lafayette, NJ 07848-0032, USA.
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Lengyel C, Varró A, Tábori K, Papp JG, Baczkó I. Combined pharmacological block of I(Kr) and I(Ks) increases short-term QT interval variability and provokes torsades de pointes. Br J Pharmacol 2007; 151:941-51. [PMID: 17533421 PMCID: PMC2042930 DOI: 10.1038/sj.bjp.0707297] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 02/23/2007] [Accepted: 02/25/2007] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND PURPOSE Assessing the proarrhythmic potential of compounds during drug development is essential. However, reliable prediction of drug-induced torsades de pointes arrhythmia (TdP) remains elusive. Along with QT interval prolongation, assessment of the short-term variability of the QT interval (STV(QT)) may be a good predictor of TdP. We investigated the relative importance of I(Ks) and I(Kr) block in development of TdP together with correlations between QTc interval, QT interval variability and incidence of TdP. EXPERIMENTAL APPROACH ECGs were recorded from conscious dogs and from anaesthetized rabbits given the I(Kr) blocker dofetilide (DOF), the I(Ks) blocker HMR-1556 (HMR) and their combination, intravenously. PQ, RR and QT intervals were measured and QTc and short-term variability of RR and QT intervals calculated. KEY RESULTS DOF increased QTc interval by 20% in dogs and 8% in rabbits. HMR increased QTc in dogs by 12 and 1.9% in rabbits. Combination of DOF+HMR prolonged QTc by 33% in dogs, by 16% in rabbits. DOF or HMR given alone in dogs or HMR given alone in rabbits induced no TdP. Incidence of TdP increased after DOF+HMR combinations in dogs (63%) and following HMR+DOF (82%) and DOF+HMR combinations (71%) in rabbits. STV(QT) markedly increased only after administration of DOF+HMR combinations in both dogs and rabbits. CONCLUSION AND IMPLICATIONS STV(QT) was markedly increased by combined pharmacological block of I(Kr) and I(Ks) and may be a better predictor of subsequent TdP development than the measurement of QTc interval prolongation.
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Affiliation(s)
- C Lengyel
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged Szeged, Hungary
- 1st Department of Internal Medicine, Faculty of Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged Szeged, Hungary
| | - A Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged Szeged, Hungary
- Research Unit for Cardiovascular Pharmacology, Hungarian Academy of Sciences Szeged, Hungary
| | - K Tábori
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged Szeged, Hungary
| | - J G Papp
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged Szeged, Hungary
- Research Unit for Cardiovascular Pharmacology, Hungarian Academy of Sciences Szeged, Hungary
| | - I Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged Szeged, Hungary
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McBride BF, Min B, Kluger J, Guertin D, Henyan NN, Coleman CI, Silver BB, White CM. An evaluation of the impact of oral magnesium lactate on the corrected QT interval of patients receiving sotalol or dofetilide to prevent atrial or ventricular tachyarrhythmia recurrence. Ann Noninvasive Electrocardiol 2006; 11:163-9. [PMID: 16630091 PMCID: PMC7313317 DOI: 10.1111/j.1542-474x.2006.00098.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Intravenous magnesium reduces the QTc interval of patients receiving ibutilide. Whether oral magnesium can reduce the QTc interval associated with oral sotalol and dofetilide is not known. This study was undertaken to evaluate the impact of oral magnesium on the QTc interval and whether an inherent intracellular magnesium deficiency exists among patients with arrhythmias. METHODS Participants receiving sotalol or dofetilide for atrial or ventricular arrhythmias were randomized to receive magnesium l-lactate (504 mg elemental magnesium daily, Niche Pharmaceuticals, Roanoke, TX) or placebo for 48 hours. A 12-lead electrocardiogram (ECG) was obtained at baseline, 3 hours, and 51 hours after dosing to correspond to the Tmax after oral ingestion. The QTc interval was measured from the ECGs and compared between groups. Intracellular magnesium concentrations were determined by energy-dispersive x-ray analysis at baseline and 51 hours after dosing (Intracellular Diagnostics, Inc., Foster City, CA). RESULTS The QTc interval reductions from baseline were greater in the magnesium group than placebo at 3 and 51 hours (P = 0.015 and P < 0.001, respectively). Sixty-three percent of patients (regardless of experimental group) had baseline intracellular magnesium concentrations below the normal reference range of 33.9-41.9 mEq/IU, with an average level of 32.6 +/- 2.2 mEq/IU. CONCLUSIONS Oral magnesium l-lactate raises intracellular magnesium concentrations and lowers the QTc interval of patients receiving sotalol or dofetilide.
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Affiliation(s)
- Brian F. McBride
- School of Pharmacy, University of Connecticut, Storrs, CT
- Drug Information, Hartford Hospital, Hartford, CT
| | - Bokyung Min
- School of Pharmacy, University of Connecticut, Storrs, CT
- Drug Information, Hartford Hospital, Hartford, CT
| | - Jeffrey Kluger
- School of Medicine, University of Connecticut, Farmington, CT
- Divisions of Cardiology
| | | | - Nickole N. Henyan
- School of Pharmacy, University of Connecticut, Storrs, CT
- Drug Information, Hartford Hospital, Hartford, CT
| | - Craig I. Coleman
- School of Pharmacy, University of Connecticut, Storrs, CT
- Drug Information, Hartford Hospital, Hartford, CT
| | | | - C. Michael White
- School of Pharmacy, University of Connecticut, Storrs, CT
- Drug Information, Hartford Hospital, Hartford, CT
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Kovács A, Magyar J, Bányász T, Nánási PP, Szénási G. Beta-adrenoceptor activation plays a role in the reverse rate-dependency of effective refractory period lengthening by dofetilide in the guinea-pig atrium, in vitro. Br J Pharmacol 2003; 139:1555-63. [PMID: 12922944 PMCID: PMC1573989 DOI: 10.1038/sj.bjp.0705395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2003] [Revised: 04/18/2003] [Accepted: 05/22/2003] [Indexed: 11/08/2022] Open
Abstract
1. Blockers of the rapid component of the delayed rectifier potassium current (I(Kr)) prolong cardiac action potential duration (APD) and effective refractory period (ERP) in a reverse rate-dependent manner. Since activation of beta-adrenoceptors attenuates prolongation of APD evoked by I(Kr) blockers, rate-dependent neuronal noradrenaline liberation in the myocardium may contribute to the reverse rate-dependent nature of the effects of I(Kr) blockers. In order to test this hypothesis, we studied the effects of dofetilide, a pure I(Kr) blocker, on ERP after activation or blockade of beta-adrenoceptors and after catecholamine depletion in guinea-pig left atrial myocardium paced at 3, 2 and 1 Hz, in vitro. 2. Dofetilide (100 nM) lengthened ERP in a reverse rate-dependent manner in the left atrial myocardium of guinea-pigs. Strong activation of beta-adrenoceptors using 10 nM isoproterenol abolished the dofetilide-induced lengthening of ERP at all pacing rates. 3. Blockade of the beta-adrenoceptors with metoprolol (1 micro M), atenolol (3 micro M) or propranolol (300 nM) increased the dofetilide-evoked prolongation of ERP at 3 and 2 Hz, but not at 1 Hz. As a consequence, metoprolol attenuated while propranolol and atenolol fully eliminated the reverse rate-dependent nature of the dofetilide-induced ERP lengthening. In catecholamine-depleted atrial preparations of the guinea-pig (24 h pretreatment with 5 mg kg(-1) reserpine i.p.), the effect of dofetilide on ERP was not frequency dependent, and propranolol did not alter the effects of dofetilide. 4. In contrast to results obtained in guinea-pig atrial preparations, propranolol failed to change the reverse rate-dependent effect of dofetilide on ERP in the right ventricular papillary muscles of rabbits and guinea-pigs. 5. As an indication of the functional consequences of rate-dependent noradrenaline liberation, propranolol decreased twitch tension at 3 and 2 Hz but not at 1 Hz in the atrial myocardium of control guinea-pigs, whereas no such effect was detected in catecholamine-depleted atrial preparations. Propranolol failed to change contractility of ventricular myocardium in guinea-pigs and rabbits. 6. It is concluded that rate-dependent noradrenaline release and the ensuing beta-adrenoceptor activation contributed to the reverse rate-dependent nature of ERP prolongation caused by I(Kr) blockers in isolated guinea-pig atrial myocardium.
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Affiliation(s)
- Anikó Kovács
- Pharmacology Laboratory I, EGIS Pharmaceuticals Ltd., Keresztúri út 34, Budapest 10, PO Box 100, Budapest H-1475, Hungary
| | - János Magyar
- Department of Physiology, Medical University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Medical University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Medical University of Debrecen, Debrecen, Hungary
| | - Gábor Szénási
- Pharmacology Laboratory I, EGIS Pharmaceuticals Ltd., Keresztúri út 34, Budapest 10, PO Box 100, Budapest H-1475, Hungary
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Biliczki P, Virág L, Iost N, Papp JG, Varró A. Interaction of different potassium channels in cardiac repolarization in dog ventricular preparations: role of repolarization reserve. Br J Pharmacol 2002; 137:361-8. [PMID: 12237256 PMCID: PMC1573503 DOI: 10.1038/sj.bjp.0704881] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1 The aim of this study was to investigate the possible role of the interaction of different potassium channels in dog ventricular muscle, by applying the conventional microelectrode and whole cell patch-clamp techniques at 37 degrees C. 2 Complete block of I(Kr) by 1 micro M dofetilide lengthened action potential duration (APD) by 45.6+/-3.6% at 0.2 Hz (n=13). Chromanol 293B applied alone at 10 micro M (a concentration which selectively blocks I(Ks)) did not markedly lengthen APD (<7%), but when repolarization had already been prolonged by complete I(Kr) block with 1 micro M dofetilide, inhibition of I(Ks) with 10 micro M chromanol 293B substantially delayed repolarization by 38.5+/-8.2% at 0.2 Hz (n=6). 3 BaCl(2), at a concentration of 10 micro M which blocks I(Kl) without affecting other currents, lengthened APD by 33.0+/-3.1% (n=11), but when I(Kr) was blocked with 1 micro M dofetilide, 10 micro M BaCl(2) produced a more excessive rate dependent lengthening in APD, frequently (in three out of seven preparations) initiating early afterdepolarizations. 4 These findings indicate that if only one type of potassium channels is inhibited in dog ventricular muscle, excessive APD lengthening is not likely to occur. Dog ventricular myocytes seem to repolarize with a strong safety margin ('repolarization reserve'). However, when this normal 'repolarization reserve' is attenuated, otherwise minimal or moderate potassium current inhibition can result in excessive and potentially proarrhythmic prolongation of the ventricular APD. Therefore, application of drugs which are able to block more than one type of potassium channel is probably more hazardous than the use of a specific inhibitor of one given sort of potassium channel, and when simultaneous blockade of several kinds of potassium channel may be presumed, a detailed study is needed to define the determinants of 'repolarization reserve'.
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Affiliation(s)
- Péter Biliczki
- Department of Pharmacology & Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - László Virág
- Department of Pharmacology & Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Norbert Iost
- Division of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Julius Gy Papp
- Department of Pharmacology & Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
- Division of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - András Varró
- Department of Pharmacology & Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
- Author for correspondence:
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Allen MJ, Oliver SD, Newgreen MW, Nichols DJ. Pharmacodynamic effect of continuous vs intermittent dosing of dofetilide on QT interval. Br J Clin Pharmacol 2002; 53:59-65. [PMID: 11849196 PMCID: PMC1874554 DOI: 10.1046/j.0306-5251.2001.01511.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2000] [Accepted: 08/07/2001] [Indexed: 11/20/2022] Open
Abstract
AIMS To investigate the pharmacokinetics and pharmacodynamics of dofetilide 1 mg twice daily continuously for 24 days compared with intermittent single dose treatments. METHODS A randomized, single-blinded, placebo-controlled, parallel-group, multiple-dose study design was utilized. Healthy male volunteer subjects were randomized into three groups. Group 1 received dofetilide 1.0 mg twice daily for 23 days and once on day 24. Group 2 received matching placebo capsules under the same regimen as group 1. Group 3 received a single dose of dofetilide 1.0 mg on days 1, 5, 10, 17, and 24 with identical placebo capsules administered at all other times to match the dosing pattern of the other groups. RESULTS Continuous administration of dofetilide resulted in the achievement of steady-state concentrations by day 5. Pharmacokinetic parameters following intermittent treatment showed no accumulation. Maximum daily QTc interval (mean +/- s.e. mean) increased in response to continuous twice-daily dofetilide from baseline (373 +/- 5) to day 2 (453 +/- 9) but thereafter decreased slightly, but not beyond day 5, by which time the mean maximum QTc was 440 +/- 7 ms. In contrast, single doses of dofetilide in the intermittently treated group led to reproducible increases in QTc. Thus mean (+/- s.e. mean) maximum QTc increased from a baseline of 387 +/- 7-467 +/- 14, 467 +/- 18, 469 +/- 14 and 458 +/- 10 ms on days 5, 10, 17 and 24, respectively. In view of the pharmacokinetic accumulation on continuous dosing, the attenuation of responsiveness is best represented by the slope of the QTc vs plasma concentration relationship. In the continuously treated group, an initial decrease in the value of the mean slope between day 1 (14.2 +/- 1.7 ms/ng ml(-1)) and day 5 (9.1 +/- 0.8 ms/ng ml(-1)) did not progress beyond day 5. The mean difference in slopes (95% CI) between the intermittent and continuously treated groups were 4.4 (1.3, 7.4) on day 5, 4.9 (1.6, 8.2) on day 10, 5.2 (1.1, 9.2) on day 17 and 4.4 (0.4, 8.4) on day 24. CONCLUSIONS With continuous twice-daily administration the QT interval responsiveness to dofetilide is greater after the first dose than it is at steady state. After day 5 the relationship between dofetilide plasma concentration and its QT interval effect is predictable and stable over time.
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Affiliation(s)
- Michael J Allen
- Pfizer Global Research and Development, Ramsgate Road, Sandwich CT13 9NJ, Kent UK.
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Barrett TD, Hennan JK, Fischbach PS, O'Neill BP, Driscoll EM, Lucchesi BR. Tedisamil and dofetilide-induced torsades de pointes, rate and potassium dependence. Br J Pharmacol 2001; 132:1493-500. [PMID: 11264243 PMCID: PMC1572702 DOI: 10.1038/sj.bjp.0703967] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Tedisamil is a bradycardiac agent that prolongs the QT interval of the ECG and prevents cardiac arrhythmias. Given this profile, tedisamil might be expected to have proarrhythmic actions similar to Class III antiarrhythmic drugs. To address this question, the actions of dofetilide and tedisamil were examined in rabbit isolated hearts in which bradycardia was induced by AV ablation. 2. The QT interval was prolonged in a reverse rate-dependent fashion by dofetilide (3 and 30 nM) and tedisamil (0.3 and 3 microM). 3. Torsades de pointes was observed in 1/7 hearts treated with 3 nM dofetilide and 0/7 hearts treated with 0.3 microM tedisamil. The incidence of torsades de pointes was increased to 5/7 in hearts treated with 30 nM dofetilide and to 7/7 in hearts treated with 3 microM tedisamil (both P < 0.05 vs control). 4. The actions of 30 nM dofetilide and 3 microM tedisamil were also examined in hearts paced at 50, 100, 200 and 50 beats min(-1) successively. Both drugs caused torsades de pointes in 5/5 hearts paced at 50 beats min(-1); however, the incidence was reduced to 0/5 during pacing at 200 beats min(-1). Thus, drug-induced proarrhythmia was bradycardia-dependent. 5. Drug-induced prolongation of the interval between the peak and end of the T-wave (QTa-e) was reverse rate-dependent and was associated with the occurrence of torsades de pointes (r = 0.91, P < 0.01). 6. The results suggest that tedisamil, like dofetilide, presents a risk for development of torsades de pointes.
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Affiliation(s)
- Terrance D Barrett
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, MI 48019-0632, U.S.A
| | - James K Hennan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, MI 48019-0632, U.S.A
| | - Peter S Fischbach
- Department of Pediatrics and Communicable Diseases, Division of Pediatric Cardiology, University of Michigan Medical School, Ann Arbor, Michigan, MI 48019-0632, U.S.A
| | - Brian P O'Neill
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, MI 48019-0632, U.S.A
| | - Edward M Driscoll
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, MI 48019-0632, U.S.A
| | - Benedict R Lucchesi
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, MI 48019-0632, U.S.A
- Author for correspondence:
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Abstract
AIMS The aim of this open-label, placebo-controlled, randomized, four-period crossover study was to determine the effects of cimetidine and ranitidine on the pharmacokinetics and pharmacodynamics of a single dose of dofetilide. METHODS Twenty healthy male subjects received 100 or 400 mg twice daily of cimetidine, 150 mg twice daily of ranitidine, or placebo for 4 days. On the second day, a single oral 500 microg dose of dofetilide was administered immediately after the morning doses of cimetidine, ranitidine, or placebo. Treatment periods were separated by 1-2 weeks. Pharmacokinetic parameters were determined from plasma and urinary dofetilide concentrations; prolongation of the QTc interval was determined from three-lead electrocardiograms. RESULTS Ranitidine did not significantly affect the pharmacokinetics or pharmacodynamics of dofetilide; however, a dose-dependent increase in exposure to dofetilide was observed with cimetidine. When dofetilide was administered with 100 and 400 mg of cimetidine, the area under the plasma concentration-time curve of dofetilide increased by 11% and 48% and the maximum plasma dofetilide concentration increased by 11% and 29%, respectively. The respective cimetidine doses reduced renal clearance of dofetilide by 13% and 33% and nonrenal clearance by 5% and 21%. Dofetilide-induced prolongation of the QTc interval was enhanced by cimetidine; the mean maximum change in QTc interval from baseline was increased by 22% and 33% with 100 and 400 mg of cimetidine, respectively. However, the relationship between the prolongation of the QTc interval and plasma dofetilide concentrations was unaffected by cimetidine or ranitidine; a 1 ng ml-1 increase in plasma dofetilide concentration produced a 17-19 ms prolongation of the QTc interval. Dofetilide was well tolerated, with no treatment-related adverse events or laboratory abnormalities. CONCLUSIONS These results suggest that cimetidine increased dofetilide exposure by inhibiting renal tubular dofetilide secretion, whereas ranitidine did not. This effect is not an H2-receptor antagonist class effect but is specific to cimetidine. If therapy with an H2-receptor antagonist is required, it is recommended that cimetidine at all doses be avoided; since ranitidine has no effect on dofetilide pharmacokinetics or prolongation of the QTc interval, it can be seen as a suitable alternative.
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Affiliation(s)
- S Abel
- Pfizer Central Research, Sandwich, UK
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