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Carpio EF, Gomez JF, Sebastian R, Lopez-Perez A, Castellanos E, Almendral J, Ferrero JM, Trenor B. Optimization of Lead Placement in the Right Ventricle During Cardiac Resynchronization Therapy. A Simulation Study. Front Physiol 2019; 10:74. [PMID: 30804805 PMCID: PMC6378298 DOI: 10.3389/fphys.2019.00074] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 01/22/2019] [Indexed: 12/18/2022] Open
Abstract
Patients suffering from heart failure and left bundle branch block show electrical ventricular dyssynchrony causing an abnormal blood pumping. Cardiac resynchronization therapy (CRT) is recommended for these patients. Patients with positive therapy response normally present QRS shortening and an increased left ventricle (LV) ejection fraction. However, around one third do not respond favorably. Therefore, optimal location of pacing leads, timing delays between leads and/or choosing related biomarkers is crucial to achieve the best possible degree of ventricular synchrony during CRT application. In this study, computational modeling is used to predict the optimal location and delay of pacing leads to improve CRT response. We use a 3D electrophysiological computational model of the heart and torso to get insight into the changes in the activation patterns obtained when the heart is paced from different regions and for different atrioventricular and interventricular delays. The model represents a heart with left bundle branch block and heart failure, and allows a detailed and accurate analysis of the electrical changes observed simultaneously in the myocardium and in the QRS complex computed in the precordial leads. Computational simulations were performed using a modified version of the O'Hara et al. action potential model, the most recent mathematical model developed for human ventricular electrophysiology. The optimal location for the pacing leads was determined by QRS maximal reduction. Additionally, the influence of Purkinje system on CRT response was assessed and correlation analysis between several parameters of the QRS was made. Simulation results showed that the right ventricle (RV) upper septum near the outflow tract is an alternative location to the RV apical lead. Furthermore, LV endocardial pacing provided better results as compared to epicardial stimulation. Finally, the time to reach the 90% of the QRS area was a good predictor of the instant at which 90% of the ventricular tissue was activated. Thus, the time to reach the 90% of the QRS area is suggested as an additional index to assess CRT effectiveness to improve biventricular synchrony.
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Affiliation(s)
- Edison F Carpio
- Centre for Research and Innovation in Bioengineering (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | - Juan F Gomez
- Centre for Research and Innovation in Bioengineering (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | - Rafael Sebastian
- Computational Multiscale Simulation Lab (CoMMLab), Department of Computer Science, Universitat de València, Valencia, Spain
| | - Alejandro Lopez-Perez
- Centre for Research and Innovation in Bioengineering (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | - Eduardo Castellanos
- Electrophysiology Laboratory and Arrhythmia Unit, Grupo HM Hospitales, Hospital Monteprincipe, University CEU-San Pablo, Madrid, Spain
| | - Jesus Almendral
- Electrophysiology Laboratory and Arrhythmia Unit, Grupo HM Hospitales, Hospital Monteprincipe, University CEU-San Pablo, Madrid, Spain
| | - Jose M Ferrero
- Centre for Research and Innovation in Bioengineering (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | - Beatriz Trenor
- Centre for Research and Innovation in Bioengineering (Ci2B), Universitat Politècnica de València, Valencia, Spain
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Sardu C, Paolisso P, Sacra C, Santamaria M, de Lucia C, Ruocco A, Mauro C, Paolisso G, Rizzo MR, Barbieri M, Marfella R. Cardiac resynchronization therapy with a defibrillator (CRTd) in failing heart patients with type 2 diabetes mellitus and treated by glucagon-like peptide 1 receptor agonists (GLP-1 RA) therapy vs. conventional hypoglycemic drugs: arrhythmic burden, hospitalizations for heart failure, and CRTd responders rate. Cardiovasc Diabetol 2018; 17:137. [PMID: 30348145 PMCID: PMC6196445 DOI: 10.1186/s12933-018-0778-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/10/2018] [Indexed: 01/08/2023] Open
Abstract
Objectives To evaluate clinical outcomes in patients with diabetes, treated by cardiac resynchronization therapy with a defibrillator (CRT-d), and glucagon-like peptide 1 receptor agonists (GLP-1 RA) in addition to conventional hypoglycemic therapy vs. CRTd patients under conventional hypoglycemic drugs. Background Patients with diabetes treated by CRTd experienced an amelioration of functional New York Association Heart class, reduction of hospital admissions, and mortality, in a percentage about 60%. However, about 40% of CRTd patients with diabetes experience a worse prognosis. Materials and methods We investigated the 12-months prognosis of CRTd patients with diabetes, previously treated with hypoglycemic drugs therapy (n 271) vs. a matched cohort of CRTd patients with diabetes treated with GLP-1 RA in addition to conventional hypoglycemic therapy (n 288). Results At follow up CRTd patients with diabetes treated by GLP-1 RA therapy vs. CRTd patients with diabetes that did not receive GLP-1 RA therapy, experienced a significant reduction of NYHA class (p value < 0.05), associated to higher values of 6 min walking test (p value < 0.05), and higher rate of CRTd responders (p value < 0.05). GLP-1 RA patients vs. controls at follow up end experienced lower AF events (p value < 0.05), lower VT events (p value < 0.05), lower rate of hospitalization for heart failure worsening (p value < 0.05), and higher rate of CRTd responders (p value < 0.05). To date, GLP-1 RA therapy may predict a reduction of AF events (HR 0.603, CI [0.411–0.884]), VT events (HR 0.964, CI [0.963–0.992]), and hospitalization for heart failure worsening (HR 0.119, CI [0.028–0.508]), and a higher CRT responders rate (HR 3.707, CI [1.226–14.570]). Conclusions GLP-1 RA drugs in addition to conventional hypoglycemic therapy may significantly reduce systemic inflammation and circulating BNP levels in CRTd patients with diabetes, leading to a significant improvement of LVEF and of the 6 min walking test, and to a reduction of the arrhythmic burden. Consequently, GLP-1 RA drugs in addition to conventional hypoglycemic therapy may reduce hospital admissions for heart failure worsening, by increasing CRTd responders rate. Trial registration NCT03282136. Registered 9 December 2017 “retrospectively registered”
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Affiliation(s)
- Celestino Sardu
- Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, University of Campania "Luigi Vanvitelli", Piazza Miraglia, 2, 80138, Naples, Italy.
| | - Pasquale Paolisso
- Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, University of Campania "Luigi Vanvitelli", Piazza Miraglia, 2, 80138, Naples, Italy
| | - Cosimo Sacra
- Cardiovascular and Arrhythmias Department, John Paul II Research and Care Foundation, Campobasso, Italy
| | - Matteo Santamaria
- Cardiovascular and Arrhythmias Department, John Paul II Research and Care Foundation, Campobasso, Italy
| | - Claudio de Lucia
- Center for Translational Medicine, Temple University, Philadelphia, USA
| | - Antonio Ruocco
- Cardiovascular Diseases Department, Cardarelli Hospital, Naples, Italy
| | - Ciro Mauro
- Cardiovascular Diseases Department, Cardarelli Hospital, Naples, Italy
| | - Giuseppe Paolisso
- Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, University of Campania "Luigi Vanvitelli", Piazza Miraglia, 2, 80138, Naples, Italy
| | - Maria Rosaria Rizzo
- Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, University of Campania "Luigi Vanvitelli", Piazza Miraglia, 2, 80138, Naples, Italy
| | - Michelangela Barbieri
- Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, University of Campania "Luigi Vanvitelli", Piazza Miraglia, 2, 80138, Naples, Italy
| | - Raffaele Marfella
- Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, University of Campania "Luigi Vanvitelli", Piazza Miraglia, 2, 80138, Naples, Italy
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Behar JM, Claridge S, Jackson T, Sieniewicz B, Porter B, Webb J, Rajani R, Kapetanakis S, Carr-White G, Rinaldi CA. The role of multi modality imaging in selecting patients and guiding lead placement for the delivery of cardiac resynchronization therapy. Expert Rev Cardiovasc Ther 2016; 15:93-107. [DOI: 10.1080/14779072.2016.1252674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Jonathan M Behar
- Department of Imaging Sciences & Biomedical Engineering, King’s College London, London, UK
- Department of Cardiology, St. Thomas’ Hospital, London, UK
| | - Simon Claridge
- Department of Imaging Sciences & Biomedical Engineering, King’s College London, London, UK
- Department of Cardiology, St. Thomas’ Hospital, London, UK
| | - Tom Jackson
- Department of Imaging Sciences & Biomedical Engineering, King’s College London, London, UK
- Department of Cardiology, St. Thomas’ Hospital, London, UK
| | - Ben Sieniewicz
- Department of Imaging Sciences & Biomedical Engineering, King’s College London, London, UK
- Department of Cardiology, St. Thomas’ Hospital, London, UK
| | - Bradley Porter
- Department of Imaging Sciences & Biomedical Engineering, King’s College London, London, UK
- Department of Cardiology, St. Thomas’ Hospital, London, UK
| | - Jessica Webb
- Department of Imaging Sciences & Biomedical Engineering, King’s College London, London, UK
- Department of Cardiology, St. Thomas’ Hospital, London, UK
| | - Ronak Rajani
- Department of Cardiology, St. Thomas’ Hospital, London, UK
| | | | | | - Christopher A Rinaldi
- Department of Imaging Sciences & Biomedical Engineering, King’s College London, London, UK
- Department of Cardiology, St. Thomas’ Hospital, London, UK
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Dickstein K, Vardas PE, Auricchio A, Daubert JC, Linde C, McMurray J, Ponikowski P, Priori SG, Sutton R, van Veldhuisen DJ, Auricchio A, Bax J, Ceconi C, Dean V, Filippatos G, Funck-Brentano C, Hobbs R, Kearney P, McDonagh T, Popescu BA, Reiner Z, Sechtem U, Sirnes PA, Tendera M, Vardas P, Widimsky P, Tendera M, Anker SD, Blanc JJ, Gasparini M, Hoes AW, Israel CW, Kalarus Z, Merkely B, Swedberg K, Camm AJ. 2010 focused update of ESC Guidelines on device therapy in heart failure: an update of the 2008 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure and the 2007 ESC Guidelines for cardiac and resynchronization therapy. Developed with the special contribution of the Heart Failure Association and the European Heart Rhythm Association. Eur J Heart Fail 2011; 12:1143-53. [PMID: 20965877 DOI: 10.1093/eurjhf/hfq192] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Stockburger M. [Cardiac resynchronization in narrow QRS and less affected exercise capacity]. Herzschrittmacherther Elektrophysiol 2011; 22:16-20. [PMID: 21344232 DOI: 10.1007/s00399-011-0118-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Cardiac resynchronization (CRT) through atrio-biventricular pacemaker therapy is now a well established treatment option for severely symptomatic patients with advanced systolic heart failure (HF) and intraventricular conduction delay, especially left bundle branch block. The purpose of this article is to address possible applications of biventricular pacing beyond the classical CRT indication. In particular, a summary is given of available information on CRT in patients with symptomatic systolic HF, but narrow QRS complex, and those with wide QRS, but less pronounced or even absent clinical HF signs.
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Affiliation(s)
- M Stockburger
- Medizinische Klinik mit Schwerpunkt Kardiologie, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Deutschland.
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Dickstein K, Vardas PE, Auricchio A, Daubert JC, Linde C, McMurray J, Ponikowski P, Priori SG, Sutton R, van Veldhuisen DJ. 2010 Focused Update of ESC Guidelines on device therapy in heart failure: an update of the 2008 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure and the 2007 ESC Guidelines for cardiac and resynchronization therapy. Developed with the special contribution of the Heart Failure Association and the European Heart Rhythm Association. Europace 2011; 12:1526-36. [PMID: 20974767 DOI: 10.1093/europace/euq392] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Dickstein K, Vardas PE, Auricchio A, Daubert JC, Linde C, McMurray J, Ponikowski P, Priori SG, Sutton R, van Veldhuisen DJ. 2010 Focused Update of ESC Guidelines on device therapy in heart failure: An update of the 2008 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure and the 2007 ESC guidelines for cardiac and resynchronization therapy Developed with the special contribution of the Heart Failure Association and the European Heart Rhythm Association. Eur Heart J 2010; 31:2677-87. [PMID: 20801924 DOI: 10.1093/eurheartj/ehq337] [Citation(s) in RCA: 246] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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GOLD MICHAELR, NIAZI IMRAN, GIUDICI MICHAEL, LEMAN ROBERTB, STURDIVANT JOHNL, KIM MICHAELH, WAGGONER ALAND, DING JIANG, ARCOT-KRISHNAMURTHY SHANTHA, DAUM DOUGLAS, YU YINGHONG. Acute Hemodynamic Effects of Atrial Pacing with Cardiac Resynchronization Therapy. J Cardiovasc Electrophysiol 2009; 20:894-900. [DOI: 10.1111/j.1540-8167.2009.01460.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Effect of cardiac resynchronization therapy on the incidence of electrical storm. Int J Cardiol 2009; 143:330-6. [PMID: 19359057 DOI: 10.1016/j.ijcard.2009.03.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 01/21/2009] [Accepted: 03/09/2009] [Indexed: 01/29/2023]
Abstract
BACKGROUND Hemodynamic improvement from biventricular pacing is well documented; however, its electrophysiologic effects have not been systematically studied. In this study, incidence and risk factors for electrical storm (ES) were investigated in 729 ICD and biventricular defibrillator (CRT-D) heart failure patients. METHODS 168 consecutive CRT-D and 561 ICD patients were retrospectively analyzed for the occurrence of VT/VF and predisposing factors. Electrical storm was defined as ventricular tachycardia or fibrillation ≥3 times during 24 h. Mean follow-up was 41 months. RESULTS In 168 CRT-D patients only one patient experienced electrical storm compared to 39 patients out of 561 ICD patients (0.6% vs. 7%, p<0.01). 33% of the patients with electrical storm died within one year. In the CRT-D group 81 patients (48%) developed VT or VF and received at least one appropriate therapy, compared to 281 patients (50%) in the ICD group. Mean ejection fraction was 21.7% in the CRT-D group and 34.7% (p<0.01) in the ICD group. Stratifying the patients according to primary or secondary prevention and ejection fraction demonstrated that VT/VF clusters were significantly associated with ICD indication for secondary prevention, previous myocardial infarction and LVEF<30%. CONCLUSION The development of electrical storm is accompanied with a highly increased mortality risk even if an ICD/CRT-D is implanted. In CRT-D patients electrical storm is much less common than in ICD patients. Secondary prevention and ejection fraction<30% are predictors of electrical storm. Beside hemodynamic improvements cardiac resynchronization therapy may reduce the arrhythmia burden in heart failure patients.
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Eisen HJ. What can post market registries tell us about the use of cardiac resynchronization therapy? Curr Heart Fail Rep 2007; 4:39-42. [PMID: 17386184 DOI: 10.1007/s11897-007-0024-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cardiac resynchronization therapy (CRT) has become an established therapeutic option for patients with dilated cardiomyopathies and New York Heart Association class III congestive heart failure symptoms who also have a widened QRS complex on their electrocardiograms (generally > 120 ms). Results from a number of clinical trials have shown that CRT improves patients' exercise tolerance, quality of life, and survival. There is further evidence that CRT has structural effects on the heart with improved cardiac function. Despite these salutary results, clinical trials in CRT study prespecified populations that fit the inclusion criteria for these trials. Many patients have been excluded from these clinical trials and yet may potentially benefit from CRT. Evaluation of the effects of CRT on these populations might reveal the potential to expand the use of this therapy in larger numbers of patients to CRT who may not have been included in the clinical trial. This review article will assess the limitations of some of the clinical trials in CRT and will discuss the potential for CRT registries that are presently underway to extend the patient population that may benefit from this therapeutic option.
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Affiliation(s)
- Howard J Eisen
- Division of Cardiology, Drexel University College of Medicine, 245 North 15th Street, Philadelphia, PA 19102, USA.
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Gold MR, Niazi I, Giudici M, Leman RB, Sturdivant JL, Kim MH, Yu Y, Ding J, Waggoner AD. A prospective comparison of AV delay programming methods for hemodynamic optimization during cardiac resynchronization therapy. J Cardiovasc Electrophysiol 2007; 18:490-6. [PMID: 17313533 DOI: 10.1111/j.1540-8167.2007.00770.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION There are several methods for programming the optimal AV delay (AVD) during cardiac resynchronization therapy (CRT). These include Doppler echocardiographic measurements of mitral inflow or aortic outflow velocities, an arbitrarily fixed AVD, and calculations based on intracardiac electrogram (EGM) intervals. The present study was designed to compare the acute effects of AVD programming methods during CRT. METHODS AND RESULTS We studied 28 patients at CRT implant with invasive measurements of LV dP/dt to determine the effect of AVD during atrial sensed (AS) and atrial paced (AP) modes. The optimal AVD, defined as that resulting in the maximal LV dP/dt, was then compared with that predicted by several noninvasive methods. CRT increased LV dP/dt 11% +/- 11% during AS (heart rate: 73 +/- 14 bpm) and 17% +/- 12% during AP (heart rate: 86 +/- 12 bpm) (P < 0.001 vs AS). There was an excellent correlation between the EGM method and the maximum achievable LV dP/dt (AS: R2 = 0.99, P < 0.0001, AP: R2 = 0.96, P < 0.0001) and this method performed better than other techniques. CONCLUSIONS An electrogram-based optimization method accurately predicts the optimal AVD among patients over a wide range of QRS intervals during CRT in both AS and AP modes. This simple technique may obviate the need for echocardiography for AVD programming.
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Affiliation(s)
- Michael R Gold
- Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Martin DO, Stolen KQ, Brown S, Yu Y, Christie C, Doshi SK, Smith JM, Gold MR, Day JD. Pacing Evaluation-Atrial SUpport Study in Cardiac Resynchronization Therapy (PEGASUS CRT): design and rationale. Am Heart J 2007; 153:7-13. [PMID: 17174627 DOI: 10.1016/j.ahj.2006.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Accepted: 10/14/2006] [Indexed: 11/21/2022]
Abstract
BACKGROUND Cardiac resynchronization therapy (CRT) has been demonstrated to be an effective heart failure (HF) therapy. All pivotal trials of CRT to date have used atrial-synchronous biventricular pacing wherein there is no or minimal atrial pacing. In clinical practice, however, physicians often program CRT devices to have atrial rate support pacing, either by increasing the lower rate limit or by activating the rate sensor. OBJECTIVE The purpose of this study is to evaluate the effect of empiric atrial support pacing in patients with HF who have received a CRT defibrillator (CRT-D) device. METHODS PEGASUS CRT is a multicenter, 3-arm, randomized clinical trial of approximately 1200 patients receiving a CRT-D device. For the first 6 weeks after implant, devices are programmed to DDD with a lower rate limit of 40 beats/min. At 6 weeks, patients are randomized to DDD-40, DDD-70, or DDDR-40. All randomized patients are followed for 1 year, and at each visit, mortality, HF events, quality of life, New York Heart Association class, and atrial and ventricular arrhythmic episodes are evaluated. An exercise substudy will also be conducted, enrolling a minimum of 375 patients. Patients in this substudy will complete 2 cardiopulmonary exercise tests to evaluate the effect pacing mode has on exercise capacity. This randomized controlled trial will address whether empiric atrial support pacing is of clinical benefit to patients with HF who receive a CRT-D device.
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Affiliation(s)
- David O Martin
- Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
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13
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Shukla G, Chaudhry GM, Orlov M, Hoffmeister P, Haffajee C. Potential proarrhythmic effect of biventricular pacing: fact or myth? Heart Rhythm 2006; 2:951-6. [PMID: 16171749 DOI: 10.1016/j.hrthm.2005.05.019] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Accepted: 05/26/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND Hemodynamic improvement from biventricular pacing is well documented; however, its electrophysiologic effects have not been systematically studied. Sporadic case reports suggest a proarrhythmic effect of biventricular pacing resulting primarily in polymorphic ventricular tachycardia/ventricular fibrillation (VT/VF). OBJECTIVES The purpose of this study was to report a series of patients in whom implantation of a biventricular system resulted in VT/VF storm with predominance of monomorphic VT. METHODS In a retrospective analysis of all biventricular implants over a 4-year period at a single medical center, we identified 5 of 145 patients (3.4%) who developed VT/VF after they were upgraded to a biventricular system. All patients were male, age 71 +/- 8 years, with ejection fraction of 0.25 +/- 0.1. Four of five patients had ischemic cardiomyopathy. RESULTS All patients developed incessant VT/VF within 1 week of implantation. Monomorphic VT of single morphology was noted in 3 of 5 patients, monomorphic VT of multiple morphologies in 1, and polymorphic VT/VF in 1. VT was managed by temporary discontinuation of biventricular pacing in all patients, amiodarone in 3 of 5, sotalol in 1, and beta-blocker in 1. During 11 +/- 7 months of follow-up, 4 of 5 patients remain alive and are arrhythmia-free. CONCLUSION Biventricular pacing may result in precipitation of VT/VF storm in a minority of patients with prior history of VT/VF. This may be the first case series reporting both monomorphic and polymorphic VT after an upgrade to a system with biventricular pacing capabilities. The arrhythmias can be managed by conventional therapy and may require temporary discontinuation of left ventricular pacing. This observation is relevant to patients receiving a biventricular pacemaker without an implantable cardioverter-defibrillator backup.
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Affiliation(s)
- Gunjan Shukla
- St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02135, USA.
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Butter C, Wellnhofer E, Seifert M, Schlegl M, Hoersch W, Goehring A, Fleck E. Time course of left ventricular volumes in severe congestive heart failure patients treated by optimized AV sequential left ventricular pacing alone--a 3-dimensional echocardiographic study. Am Heart J 2006; 151:115-23. [PMID: 16368302 DOI: 10.1016/j.ahj.2005.02.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 02/02/2005] [Indexed: 11/26/2022]
Abstract
BACKGROUND This study evaluates the acute and chronic resynchronizing effects of AV sequential left ventricular (LV) pacing on LV function in patients with impaired cardiac function and conduction disorders by 3-dimensional transesophageal echocardiography. METHODS AND RESULTS Twenty-nine patients with congestive heart failure, with LV ejection fraction (LVEF) < or = 30%, QRS duration > or = 120 milliseconds, and New York Heart Association Class II to IV, were implanted with a cardiac resynchronization device using an LV lead only, according to the invasively determined hemodynamic optimal pacing site and AV delay. Patients underwent 3-dimensional transesophageal echocardiography before randomization to treatment (baseline) and at 12-month follow-up (resynchronization--12 months). Three-dimensional volumes were acquired on resynchronization and during intermittent switch-off at intrinsic depolarization. The values of stroke volume were 43.2 +/- 13.3 (intrinsic-baseline), 51.7 +/- 17.4 (intrinsic--12 months), 57.2 +/- 15.6 (resynchronization-baseline), and 64.6 +/- 18.9 (resynchronization--12 months). Analysis of variance demonstrated a significant effect of resynchronization at different periods (P < .001) and a significant time effect (P < .05) for stroke volume. Similar results were observed with ejection fraction (LVEF). No effect was observed with LV end-diastolic volume, whereas a therapy effect with no time effect was observed with LV end-systolic volume. CONCLUSIONS A significant acute increase of LV stroke volume and LVEF was found by resynchronization by LV pacing alone. A continuous improvement of LV stroke volume and LVEF occurred with time of follow-up (reverse remodeling). The initial therapeutic effect persisted during 12-month follow-up independently of time of follow-up and QRS width. No significant decrease of LV end-diastolic size during chronic resynchronization was detected in contrast to previous studies with resynchronization by biventricular pacing.
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Abstract
Sudden cardiac death (SCD) is a major healthcare problem worldwide. The majority of SCD events occur in patients with clinically recognized heart disease and most episodes result from ventricular tachyarrhythmias. Implantable cardioverter defibrillator (ICD) therapy prevents SCD in specific patient populations. Significant progress in the design and technology has been made since the Food and Drug Administration first approved the ICD in 1985. First-generation ICDs were large, were implanted in the abdomen, required a thoracotomy for placing epicardial defibrillation patches, and were nonprogrammable. Contemporary ICDs have been substantially downsized, are implanted via a transvenous approach, and are multiprogrammable. Device implantation has been simplified to be similar to that of a permanent pacemaker. In addition to treating life-threatening ventricular arrhythmias, ICDs now treat bradyarrhythmias, atrial arrhythmias, and congestive heart failure. The purpose of this article is to describe the evidence supporting the use of ICD therapy and to explain the current devices used in clinical practice.
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Affiliation(s)
- Melanie T Gura
- Pacemaker & Arrhythmia Services, The Heart Group, Inc, Akron, Ohio 44236, USA.
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Block M, Brömsen J. [Effect of CRT on morbidity and mortality]. Herzschrittmacherther Elektrophysiol 2005; 16:32-7. [PMID: 15824874 DOI: 10.1007/s00399-005-0457-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Accepted: 03/04/2005] [Indexed: 11/24/2022]
Abstract
Patients with chronic heart failure who show a left ventricular ejection fraction < or =35% and remain in NYHA class III or IV despite optimal pharmacologic treatment show less morbidity and mortality on cardiac resynchronization therapy (CRT) if the left ventricle shows asynchrony. Although only one study has shown a significant reduction of mortality about 4% less deaths per year in the first two years can be resumed. Procedure related mortality is less than 1%. By improving on average one NYHA class 10-20% less patients experience hospitalization due to heart failure in the first two years after implantation of a CRT device. Patients who are hospitalized despite CRT have on average a hospital stay below 5 days. At least 10% of patients are currently suffering surgical revisions due to infections, dislocations and high pacing thresholds of the left ventricular lead. If costs saved by less hospitalization can finance costs of CRT or even exceed the costs of CRT remains unknown.
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Affiliation(s)
- M Block
- Stiftsklinik Augustinum, Wolkerweg 16, 81375 München, Germany.
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Lindner O, Vogt J, Kammeier A, Wielepp P, Holzinger J, Baller D, Lamp B, Hansky B, Körfer R, Horstkotte D, Burchert W. Effect of cardiac resynchronization therapy on global and regional oxygen consumption and myocardial blood flow in patients with non-ischaemic and ischaemic cardiomyopathy. Eur Heart J 2004; 26:70-6. [PMID: 15615802 DOI: 10.1093/eurheartj/ehi046] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS We studied the effects of cardiac resynchronization therapy (CRT) on global and regional myocardial oxygen consumption (MVO2) and myocardial blood flow (MBF) in non-ischaemic (NICM) and ischaemic dilated cardiomyopathy (ICM). METHODS AND RESULTS Thirty-one NICM and 11 ICM patients, all of them acute responders, were investigated. MVO2 and MBF were obtained by 11C-acetate PET before and after 4 months of CRT. In NICM global MVO2 and MBF did not change during CRT, while the rate pressure product (RPP) normalized MVO2 increased (P=0.03). Before CRT regional MVO2 and MBF were highest in the lateral wall and lowest in the septum. Under therapy, MVO2 and MBF decreased in the lateral wall (P=0.045) and increased in the septum (P=0.045) resulting in a more uniform distribution. In ICM, global MVO2, MBF, and RPP did not change under CRT. Regional MVO2 and MBF showed no significant changes but a similar tendency in the lateral and septal wall to that in NICM. CONCLUSION CRT induces changes of MVO2 and MBF on a regional level with a more uniform distribution between the myocardial walls and improved ventricular efficiency in NICM. Based on the investigated parameters, CRT appears to be more effective in NICM than in ICM.
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Affiliation(s)
- Oliver Lindner
- Institute of Molecular Biophysics, Radiopharmacy, and Nuclear Medicine, Heart and Diabetes Center North Rhine-Westphalia, Georgstr. 11, D-32545 Bad Oeynhausen, Germany.
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Riedlbauchová L, Kautzner J, Hatala R, Buckingham TA. Is right ventricular outflow tract pacing an alternative to left ventricular/biventricular pacing? PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2004; 27:871-7. [PMID: 15189518 DOI: 10.1111/j.1540-8159.2004.00549.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The right ventricular apex has been used as the traditional pacing site since the development of transvenous pacing in 1959. Some studies suggest that pacing the right ventricular apex may cause remodeling and is harmful. In the past decade, there have been a multitude of studies of the hemodynamic, electrophysiological, electrocardiographic, and clinical effects of ventricular pacing at other sites. Pacing of the left ventricle singly or with biventricular pacing has emerged as an effective and safe therapy for moderate to severe congestive heart failure in patients with prolonged QRS complexes. Studies of alternate right ventricular sites, like the right ventricular outflow tract, have given mixed results. Not all patients can be treated with left ventricular pacing, which is a time-consuming and difficult procedure. Right ventricular pacing is easier and less expensive than left ventricular pacing and further study of additional right ventricular sites seems warranted.
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Affiliation(s)
- Lucie Riedlbauchová
- Department of Cardiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Auricchio A, Stellbrink C, Butter C, Sack S, Vogt J, Misier AR, Böcker D, Block M, Kirkels JH, Kramer A, Huvelle E. Clinical efficacy of cardiac resynchronization therapy using left ventricular pacing in heart failure patients stratified by severity of ventricular conduction delay. J Am Coll Cardiol 2004; 42:2109-16. [PMID: 14680736 DOI: 10.1016/j.jacc.2003.04.003] [Citation(s) in RCA: 292] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES We assessed the clinical efficacy of single-site left ventricular (LV) pacing and determined the impact of baseline conduction delay severity on the magnitude of benefit. BACKGROUND Multisite biventricular pacing can improve heart failure (HF) symptoms in patients with an intraventricular conduction delay by resynchronizing abnormal ventricular contractions and improving LV systolic function. METHODS Eighty-six patients with at least New York Heart Association functional class II HF, chronic LV systolic dysfunction, normal sinus rhythm, and a QRS interval over 120 ms were implanted for atrial-synchronized LV pacing. The single-blinded, randomized, controlled, crossover study stratified patients 1:1 by the baseline QRS interval into long (QRS >150 ms) and short (QRS 120 to 150 ms) groups, which were compared during a three-month period of active (univentricular) pacing and a three-month period of inactive (ventricular inhibited) pacing. The primary end point was peak oxygen consumption (VO(2)) followed by anaerobic threshold, distance walked in 6 min, and quality-of-life questionnaire score. PATIENTS Twelve patients were withdrawn before randomization and 17 could not complete both study periods. The short QRS group did not improve in any end point with active pacing. For the long QRS group, peak VO(2) increased 2.46 ml/min/kg (p < 0.001), the anaerobic threshold increased 1.55 ml/min/kg (p < 0.001), the distance walked in 6 min increased 47 m (p = 0.024), and the quality-of-life score improved 8.1 points (p = 0.004). CONCLUSIONS Left ventricular pacing significantly improves exercise tolerance and quality of life in patients with chronic HF, LV systolic dysfunction, and a QRS interval over 150 ms.
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Affiliation(s)
- Angelo Auricchio
- Department of Cardiology, University Hospital, Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany.
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20
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Abstract
Heart failure (HF) is responsible for an immense burden on our healthcare system. The prevalence of this disease continues to increase as a result of an aging population, successful treatment of acute coronary syndrome, and the use of new pharmacotherapies. Although pharmacotherapy with angiotensin converting enzyme inhibitors and beta-blockers shows improvement in morbidity and mortality, the overall prognosis of these patients remains poor. Cardiac transplant has limited applicability. Conduction disturbances are frequent in patients with advanced heart failure and may cause worsening systolic function and ventricular dyssynchrony. Biventricular pacing to achieve cardiac resynchronization is a recent and promising therapy for HF patients with an intraventricular conduction defect. Randomized clinical trials have substantiated that cardiac resynchronization therapy (CRT) through biventricular pacing offers significant benefit in morbidity and mortality in a select group of HF patients. Because of the high incidence of sudden cardiac death in patients with severe HF, the combination biventricular pacing with implantable cardioverter defibrillator therapy will provide additional benefit. This article provides an overview of CRT with the intent of describing ventricular dyssynchrony, the benefits of CRT, and the implications for advanced practice nurses.
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Perego GB, Chianca R, Facchini M, Frattola A, Balla E, Zucchi S, Cavaglià S, Vicini I, Negretto M, Osculati G. Simultaneous vs. sequential biventricular pacing in dilated cardiomyopathy: an acute hemodynamic study. Eur J Heart Fail 2003; 5:305-13. [PMID: 12798828 DOI: 10.1016/s1388-9842(02)00204-0] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
AIMS Simultaneous biventricular pacing improves left ventricular (LV) systolic performance in patients with dilated cardiomyopathy and intraventricular conduction delay. We tested the hypothesis that further improvements can be obtained using sequential biventricular pacing by optimizing both atrioventricular and interventricular delays. METHODS AND RESULTS In 12 patients, LV pressure, right ventricular (RV) pressure and respective rates of change of pressure (dP/dt) were acutely measured during biventricular pacing with different atrioventricular and interventricular (VVi) intervals ranging from -60 to +40 ms. The average increase vs. baseline in maximum LV dP/dt was higher for sequential than for simultaneous biventricular pacing (VDD mode: 35+/-20 vs. 29+/-18%, P<0.01; DDD mode: 38+/-23 vs. 34+/-25%, P<0.01), with a minority of patients accounting for most of the difference. The mean optimal VVi was -25+/-21 ms in VDD mode and -25+/-26 ms in DDD mode. With these settings, RV dP/dt was not significantly different from baseline. QRS shortening was not predictive of LV dP/dt increase. CONCLUSION A significant increase of LV dP/dt with no change in RV dP/dt can be obtained by sequential biventricular pacing as compared to simultaneous biventricular pacing. The highest LV dP/dt is achieved when LV is stimulated before RV. The hemodynamic advantage might be of clinical significance in selected cases.
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Affiliation(s)
- Giovanni B Perego
- Istituto Auxologico Italiano, Ospedale S. Luca, Via Spagnoletto 3, 20149 Milan, Italy.
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22
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Grimm W, Sharkova J, Funck R, Maisch B. How many patients with dilated cardiomyopathy may potentially benefit from cardiac resynchronization therapy? Pacing Clin Electrophysiol 2003; 26:155-7. [PMID: 12687803 DOI: 10.1046/j.1460-9592.2003.00007.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The clinical and electrocardiographic Marburg Cardiomyopathy database was analyzed to identify potential candidates for cardiac resynchronization therapy (CRT) with biventricular or left ventricular pacing among 566 patients with dilated cardiomyopathy (DCM). All of the following restrictive selection criteria were fulfilled by 38 patients (7%): NYHA functional class > or = 3 (n = 193, 34%), left ventricular ejection fraction (LVEF) < 30% (n = 238, 42%), sinus rhythm (n = 437, 77%), left bundle branch block (LBBB, n = 142, 25%), and QRS duration > or = 150 ms (n = 136, 24%). In 78 of the 566 patients (14%) all of the following less restrictive selection criteria were fulfilled: NYHA functional class > or = 3 (n = 193, 34%), LVEF < 35% in presence of any underlying rhythm (n = 326, 58%), QRS duration > or = 120 ms with right or left bundle branch block (n = 223, 39%). Thus, between 7% and 14% of patients with DCM were candidates for CRT depending on the application of strict versus less restrictive selection criteria.
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Affiliation(s)
- Wolfram Grimm
- Department of Cardiology, Hospital of the Philipps-University of Marburg, Baldingerstrasse, 35033 Marburg, Germany.
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23
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Stellbrink C, Nowak B. The importance of being synchronous: on the prognostic value of ventricular conduction delay in heart failure. J Am Coll Cardiol 2002; 40:2031-3. [PMID: 12475465 DOI: 10.1016/s0735-1097(02)02568-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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24
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Coletta AP, Louis AA, Clark AL, Nikitin N, Cleland JGF. Clinical trials update from the European Society of Cardiology: CARMEN, EARTH, OPTIMAAL, ACE, TEN-HMS, MAGIC, SOLVD-X and PATH-CHF II. Eur J Heart Fail 2002; 4:661-6. [PMID: 12413511 DOI: 10.1016/s1388-9842(02)00176-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
This article continues a series of reports on research developments related to the field of heart failure. Reports of presentations made at the Hot Line sessions of the European Society of Cardiology XXIV Congress held in Berlin, Germany, between 31 August and 4 September 2002 are included. Summaries of the results of the following trials are presented: CARMEN, EARTH, OPTIMAAL, ACE, TEN-HMS, MAGIC, SOLVD-X and PATH-CHF II.
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Affiliation(s)
- A P Coletta
- Department of Academic Cardiology, University of Hull, Castle Hull Hospital, Kingston-upon-Hull HU15 5JQ, Cottingham, UK.
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Tanaka H, Okishige K, Mizuno T, Kuriu K, Itoh F, Shimizu M, Akamatsu H, Tabuchi N, Arai H, Sunamori M. Temporary and permanent biventricular pacing via left ventricular epicardial leads implanted during primary cardiac surgery. THE JAPANESE JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY : OFFICIAL PUBLICATION OF THE JAPANESE ASSOCIATION FOR THORACIC SURGERY = NIHON KYOBU GEKA GAKKAI ZASSHI 2002; 50:284-9. [PMID: 12166267 DOI: 10.1007/bf03032296] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Biventricular pacing (BVP) is a new strategy for treating patients with severe congestive heart failure (CHF) and intraventricular conduction delay, but its full potential and technicalities of BVP require further evaluation. We evaluated BVP benefits in 4 patients in whom we implanted a left ventricular lead during primary cardiac surgery. METHODS Four CHF patients treated surgically between October 2000 and August 2001 underwent, at primary surgery, the implantation of leads in the right atrium, right ventricle, and left ventricle (LV) for postsurgical BVP. All patients had severe LV dysfunction and dilatation with intraventricular conduction delay. Surgeries involved CABG alone (n = 1), CABG + Dor's operation (n = 2), and tricuspid valve replacement + Maze procedure (n = 1). BVP was begun immediately after surgery in all 4 patients. Hemodynamic variables with BVP were compared to those without BVP for each patient, and the utility and technical aspects of implantation were evaluated. RESULTS BVP increased mean systemic blood pressure by 11% and mean LV stroke work index by 19% in the acute postsurgery period, and reduced mitral regurgitation. Two of the patients were implanted with a generator for permanent BVP, one at 1 month and the other at 6 months after surgery. The threshold of the LV epicardial lead of these 2 patients was below 2 V during follow-up, and BVP was successful. CONCLUSIONS Temporary BVP during the short-term after cardiac surgery improved cardiac function and decreased mitral regurgitation in all 4 of our patients. Epicardial lead implantation may thus be a useful option during surgical treatment of patients with CHF and intraventricular conduction delay if long-term permanent BVP is indicated.
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Affiliation(s)
- Hiroyuki Tanaka
- Department of Thoracic and Cardiovascular Surgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
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Auricchio A, Klein H. Beyond expectations: a decade of positive results with cardiac resynchronization therapy for heart failure. Eur Heart J Suppl 2002. [DOI: 10.1093/ehjsupp/4.suppl_d.d95] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
Cardiomyopathies are defined as diseases of the myocardium associated with cardiac dysfunction ranging from lifelong symptomless forms to major health problems such as progressive heart failure, arrhythmia, thromboembolism, and sudden cardiac death. They are classified by morphological characteristics as hypertrophic (HCM), dilated (DCM), arrhythmogenic right ventricular (ARVC), and restrictive cardiomyopathy (RCM). A familial cause has been shown in 50% of patients with HCM, 35% with DCM, and 30% with ARVC. In HCM, nine genetic loci and more than 130 mutations in ten different sarcomeric genes and in the gamma 2 subunit of AMP-activated protein kinase (AMPK) have been identified, suggesting impaired force production associated with inefficient use of ATP as the crucial disease mechanism. In DCM, 16 chromosomal loci with defects of several proteins also involved in the development of skeletal myopathies have been detected. These mutated cytoskeletal and nuclear transporter proteins may alter force transmission or disrupt nuclear function, resulting in cell death. Further DCM mutations have also been identified in sarcomeric genes, which indicates that different defects of the same protein can result in either HCM or DCM. In ARVC, six genetic loci and mutations in the cardiac ryanodine receptor, which controls electromechanical coupling, and in plakoglobin and desmoglobin (molecules involved in desmosomal cell-junction integrity), have been identified. Yet, no genetic linkage has been shown in RCM. Apart from disease-causing mutations, other factors, such as environment, genetic background, and the recently identified modifier genes of the renin-angiotensin, adrenergic, and endothelin systems are likely to result in the wide variety of RCM clinical presentations. Treatment options are symptomatic and are mainly focused on treatment of heart failure and prevention of thromboembolism and sudden death. Identification of patients with high risk for major arrhythmic events is important because implantable cardioverter defibrillators can prevent sudden death. Clinical and genetic risk stratification may lead to prospective trials of primary implantation of cardioverter defibrillators in people with hereditary cardiomyopathy.
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Affiliation(s)
- W M Franz
- Medizinische Klinik und Poliklinik Grosshadern, Klinikum der Universität München, München, Germany.
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28
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Abstract
Cardiac resynchronization refers to pacing techniques that change the degree of atrial and ventricular electromechanical asynchrony in patients with major atrial and ventricular conduction disorders. Atrial and ventricular resynchronization is usually accomplished by pacing from more than one site in an electrical chamber--atrium or ventricle--and occasionally by stimulation at a single unconventional site. Resynchronization produces beneficial hemodynamic and antiarrhythmic effects by providing a more physiologic pattern of depolarization. Atrial resynchronization may prevent atrial fibrillation in selected patients with underlying bradycardia or interatrial block. Its antiarrhythmic effect in the absence of bradycardia is unclear. Ventricular resynchronization is of far greater clinical value than atrial resynchronization. Biventricular (or single-chamber left ventricular) pacing is beneficial for patients with congestive heart failure, severe left ventricular systolic dysfunction, dilated cardiomyopathy (either ischemic or idiopathic), and a major left-sided intraventricular conduction disorder, such as left bundle branch block. The change in electrical activation from resynchronization, which has no positive inotropic effect as such, is translated into mechanical improvement with a more coordinated left ventricular contraction. Several recent randomized trials and a number of observational studies have demonstrated the long-term effectiveness of ventricular resynchronization in the above group of patients. The high incidence of sudden death among these patients has encouraged ongoing clinical trials to evaluate the benefit of a system that combines biventricular pacing and cardioversion-defibrillation into a single implantable device.
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Affiliation(s)
- S S Barold
- Broward General Hospital, Fort Lauderdale, Florida, USA
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