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Thomsen JH, Hassager C, Erlinge D, Nielsen N, Lindholm MG, Bro-Jeppesen J, Grand J, Pehrson S, Graff C, Køber LV, Kjaergaard J. Repolarization and ventricular arrhythmia during targeted temperature management post cardiac arrest. Resuscitation 2021; 166:74-82. [PMID: 34271131 DOI: 10.1016/j.resuscitation.2021.07.004] [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] [Received: 03/14/2021] [Revised: 06/28/2021] [Accepted: 07/03/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Targeted temperature management (TTM) following out-of-hospital cardiac arrest (OHCA) prolongs the QT-interval but our knowledge of different temperatures and risk of arrhythmia is incomplete. OBJECTIVE To assess whether the QTc, QT-peak (QTp) and T-peak to T-end interval (TpTe) may be useful markers of ventricular arrhythmia in contemporary post cardiac arrest treatment. METHODS An ECG-substudy of the TTM-trial (TTM at 33 °C vs. 36 °C) with serial ECGs from 680 (94%) patients. Bazett's (B) and Fridericia's (F) formula were used for heart rate correction of the QT, QTp and TpTe. Ventricular arrhythmia (VT/VF) were registered during the first three days of post cardiac arrest care. RESULTS The QT, QTc and QTp intervals were prolonged more at 33 °C compared to 36 °C and restored to similar and lower levels after rewarming. The TpTe-interval remained between 92-100 ms throughout TTM in both groups. The QTc intervals were associated with ventricular arrhythmia, but not after adjustment for cardiac arrest characteristics. The QTp-interval was not associated with risk of ventricular arrhythmia. Heart rate corrected TpTe-intervals were associated with higher risk of arrhythmia (Odds ratio (OR): TpTe(B): 1.12 (1.02-1.23, p = 0.01 TpTe(F): 1.12 (1.02-1.23, p = 0.02) per 20 ms). Further a prolonged TpTe-interval ≥ 90 ms was consistently associated with higher risk (ORadjusted: TpTe(B): 2.05 (1.25-3.37), p < 0.01, TpTe(F): 2.14 (1.32-3.49), p < 0.01). CONCLUSIONS TTM prolongs the QT-interval by prolongation of the QTp-interval without association to increased risk. The TpTe-interval is not significantly affected by core temperature, but heart rate corrected TpTe intervals are robustly associated with risk of ventricular arrhythmia. TRIAL REGISTRATION The TTM-trial is registered and accessible at ClinicalTrials.gov (Identifier: NCT01020916).
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Affiliation(s)
- Jakob Hartvig Thomsen
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark.
| | - Christian Hassager
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark
| | - David Erlinge
- Department of Cardiology, Skåne University Hospital, Lund, Sweden
| | - Niklas Nielsen
- Department of Anesthesia and Intensive Care, Helsingborg Hospital, Helsingborg, Sweden
| | - Matias Greve Lindholm
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark
| | - John Bro-Jeppesen
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark
| | - Johannes Grand
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark
| | - Steen Pehrson
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark
| | - Claus Graff
- Department of Health Science and Technology, Aalborg University, Denmark
| | - Lars V Køber
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark
| | - Jesper Kjaergaard
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital Rigshospitalet, Denmark
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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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Cvijić M, Antolič B, Klemen L, Zupan I. Repolarization heterogeneity in patients with cardiac resynchronization therapy and its relation to ventricular tachyarrhythmias. Heart Rhythm 2018; 15:1784-1790. [PMID: 29908369 DOI: 10.1016/j.hrthm.2018.06.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 04/09/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Cardiac resynchronization therapy (CRT) has been shown to induce left ventricular reverse remodeling, but little is known about its influence on ventricular repolarization. OBJECTIVE The purpose of this study was to evaluate changes in ventricular repolarization of native conduction after CRT and its relation to ventricular tachycardia (VT) and ventricular fibrillation (VF) during long-term follow-up. METHODS We prospectively included 64 patients with heart failure treated with CRT. QT interval, TpTe, and TpTe/QT ratio were analyzed from 20-minute high-resolution ECGs that were recorded at baseline and 1, 3, 6, 9, and 12 months after CRT implantation. CRT was temporary inhibited during follow-up to record intrinsic ECG. Patients with a decrease of left ventricular end-systolic volume ≥15% at 12-month follow-up (mid-term follow-up) were considered as responders. Occurrences of VT/VF during follow-up were noted. RESULTS Significant increase of repolarization heterogeneity in the first months after implantation was observed (P <.05) but then declined during 12 months of follow-up. Patients with VT/VF during long-term follow-up had higher repolarization heterogeneity at mid-term follow-up than patients without VT/VF (TpTe/QT ratio: 0.263 [0.204-0.278] vs 0.225 [0.204-0.239]; P = .045). Echocardiographic response at mid-term follow-up did not significantly influence the rate of VT/VF (log-rank P = .252). In multivariate Cox regression analysis, only high repolarization heterogeneity at mid-term follow-up (TpTe/QT ratio >0.260) was independently associated with high risk of VT/VF (hazard ratio 4.29; 95% confidence interval 1.40-13.15; P = .011). CONCLUSION CRT induces time-dependent changes in repolarization parameters in the first year after implantation. High repolarization heterogeneity at mid-term follow-up was associated with higher rate of VT/VF during long-term follow-up.
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Affiliation(s)
- Marta Cvijić
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
| | - Bor Antolič
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Luka Klemen
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Igor Zupan
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
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Güneş HM, Babur Güler G, Güler E, Demir GG, Teber MK, Kızılırmak F, Çakal B, Boztosun B. Assessment of repolarization abnormalities in baseline electrocardiograms of patients with myocarditis. Turk J Med Sci 2017; 47:1333-1339. [PMID: 29151301 DOI: 10.3906/sag-1612-39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Background/aim: Myocarditis in the acute phase usually presents with sinus tachycardia but many other arrhythmias might be seen as well. In this study we aimed to investigate repolarization abnormalities in baseline ECG of patients with myocarditis for the first time.Materials and methods: Thirty patients diagnosed with myocarditis and 25 healthy age-matched controls were included. Two different cardiologists measured corrected QT (QTc), QT dispersion (QTd), QT peak (QTp), T wave peak to T wave end (TpTe), TpTe/QT ratio, and TpTe/QTc ratio in 12-lead ECG.Results: When compared with the control group, QTp (P: 0.021), QT (P: 0.003), TpTe (P < 0.001), TpTe/QTc ratio (P < 0.001), and TpTe/QT ratio (P: 0.005) were significantly higher in patients with myocarditis. A comparison of receiver operating characteristic (ROC) curves was conducted using the Hanley and McNeil method. The area under the curve (AUC) of the electrocardiographic characteristics QT (AUC: 0.736; 95% CI [0.600-0.846]), QTP (AUC: 0.680; 95% CI [0.540-0.799]), and TpTe (AUC: 0.771; 95% CI [0.638-873]) and TpTe/QTc (AUC: 0.774; 95% CI [0.641-0.876]) and TpTe/QT (AUC: 0.726; 95% CI [0.589-0.838]) in myocarditis were not significantly different from each other but all of them were different from 0.5.Conclusion: Baseline ECGs of patients with myocarditis were associated with repolarization abnormalities. These novel findings may be one of the reasons underlying arrhythmic events in patients with myocarditis.
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Wang F, Liu J, Hong L, Liang B, Graff C, Yang Y, Christiansen M, Olesen SP, Zhang L, Kanters JK. The phenotype characteristics of type 13 long QT syndrome with mutation in KCNJ5 (Kir3.4-G387R). Heart Rhythm 2013; 10:1500-6. [PMID: 23872692 DOI: 10.1016/j.hrthm.2013.07.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND Long QT syndrome type 13 (LQT13) is caused by loss-of-function mutation in the KCNJ5-encoded cardiac G-protein-coupled inward rectifier potassium channel subtype 4 protein. The electrocardiographic (ECG) features of LQT13 are not described yet. OBJECTIVE To describe for the first time in detail the phenotype-genotype relationship of the ECG and clinical features in patients with LQT13. METHODS The 12-lead ECGs, 24-hour Holter recordings, and clinical information from KCNJ5-G387R mutation carriers of a fourth-generation Han Chinese family with LQT13 and a group of healthy Chinese individuals were analyzed. RESULTS Compared with the analysis of the healthy group (n = 8), age- and sex-matched pair analysis revealed that the mutation carriers (n = 8) had ventricular repolarization abnormality results in the prolongation of corrected QT and QTpeak intervals (P < .01); greater combined measure of repolarization morphology (T-wave morphology combination score) based on asymmetry, flatness, and notch (P < .01); and reduced low frequency/high frequency ratio of heart rate variability (P < .01) as a reflection of cardiac autonomic imbalance. Mean heart rate, time domain parameters of heart rate variability, time interval from T-wave peak to T-wave end, and T-wave amplitude were similar. CONCLUSIONS This study demonstrates for the first time the ECG features of patients with LQT13. Our data suggest that QTpeak intervals and T-wave morphology combination score may be the better parameters than the corrected QT interval to predict the phenotype-genotype relationship in patients with LQT13.
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Rautaharju PM, Zhang ZM, Gregg RE, Haisty WK, Z Vitolins M, Curtis AB, Warren J, Horaĉek MB, Zhou SH, Soliman EZ. Normal standards for computer-ECG programs for prognostically and diagnostically important ECG variables derived from a large ethnically diverse female cohort: the Women's Health Initiative (WHI). J Electrocardiol 2013; 46:707-16. [PMID: 23809992 DOI: 10.1016/j.jelectrocard.2013.05.136] [Citation(s) in RCA: 15] [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: 01/18/2013] [Indexed: 01/15/2023]
Abstract
BACKGROUND Substantial new information has emerged recently about the prognostic value for a variety of new ECG variables. The objective of the present study was to establish reference standards for these novel risk predictors in a large, ethnically diverse cohort of healthy women from the Women's Health Initiative (WHI) study. METHODS AND RESULTS The study population consisted of 36,299 healthy women. Racial differences in rate-adjusted QT end (QT(ea)) and QT peak (QT(pa)) intervals as linear functions of RR were small, leading to the conclusion that 450 and 390 ms are applicable as thresholds for prolonged and shortened QT(ea) and similarly, 365 and 295 ms for prolonged and shortened QT(pa), respectively. As a threshold for increased dispersion of global repolarization (T(peak)T(end) interval), 110 ms was established for white and Hispanic women and 120 ms for African-American and Asian women. ST elevation and depression values for the monitoring leads of each person with limb electrodes at Mason-Likar positions and chest leads at level of V1 and V2 were first computed from standard leads using lead transformation coefficients derived from 892 body surface maps, and subsequently normal standards were determined for the monitoring leads, including vessel-specific bipolar left anterior descending, left circumflex artery and right coronary artery leads. The results support the choice 150 μV as a tentative threshold for abnormal ST-onset elevation for all monitoring leads. Body mass index (BMI) had a profound effect on Cornell voltage and Sokolow-Lyon voltage in all racial groups and their utility for left ventricular hypertrophy classification remains open. CONCLUSIONS Common thresholds for all racial groups are applicable for QT(ea), and QT(pa) intervals and ST elevation. Race-specific normal standards are required for many other ECG parameters.
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Affiliation(s)
- Pentti M Rautaharju
- Epidemiological Cardiology Research Center (EPICARE), Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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