Cardiac Resynchronization Therapy in Ischemic Versus Nonischemic Cardiomyopathy: Patient-Level Meta-Analysis of 7 Randomized Clinical Trials.

Background: Data on whether cardiac resynchronization therapy (CRT) results in better clinical and echocardiographic outcomes in patients with nonischemic cardiomyopathy (NICM) vs ischemic cardiomyopathy (ICM) are conflicting.
Objectives: The authors conducted this meta-analysis of 7 clinical trials of CRT to determine the association between etiology of cardiomyopathy and clinical and echocardiographic outcomes.
Methods: The authors analyzed patient-level data using Bayesian Hierarchical Weibull survival regression modeling to determine the association between etiology of cardiomyopathy and time to all-cause death or heart failure hospitalization (HFH). Linear regression was used to assess the association between etiology of cardiomyopathy and echocardiographic measurements.
Results: Of 6,252 patients included, 4,717 (75%) were men, median age was 66 years (IQR: 58-73 years), 3,704 (59%) had ICM, and 3,778 (60%) received CRT. CRT increased the time to HFH or all-cause death (HR: 0.67; 95% credible interval [CrI]: 0.56-0.82; P < 0.001) with no difference by etiology of cardiomyopathy (HR ratio: 1.06 [95% CrI: 0.87-1.29]; P = 0.57). Likewise, CRT increased the time to all-cause death (HR: 0.71 [95% CrI: 0.55-0.93]; P = 0.019) with no difference by etiology of cardiomyopathy (HR ratio: 1.06 [95% CrI: 0.80-1.43]; P = 0.70). Echocardiographic data that were available for 2,430 (39%) patients showed that CRT improvements in left ventricular ejection fraction, left ventricular end-diastolic diameter, and left ventricular end-systolic diameter were larger for patients with NICM.
Conclusions: Although CRT led to greater increases in left ventricular ejection fraction and reductions in ventricular dimensions for patients with NICM compared with those with ICM, CRT significantly increased the time to HFH or all-cause death independently of the etiology of cardiomyopathy. Further studies on improving patient selection for CRT are needed.
Competing Interests: Funding Support and Author Disclosures Primary funding was provided by the National Heart, Lung, and Blood Institute (NHLBI) (1R01HL131754). Dr Cleland has received grants and personal fees from Pharmacosmos; personal honoraria from Abbott, AstraZeneca, Idorsia, Myokardia, NI Medical, Novartis, Servier, and Torrent Pharmaceuticals; grants and personal honoraria from Amgen/Cytokinetics, Bayer, Bristol Myers Squibb, Johnson & Johnson, Medtronic, Vifor, and Viscardia; and personal honoraria and nonfinancial support from Boehringer-Ingelheim outside of the submitted work. Dr Curtis serves on medical advisory boards for Janssen Pharmaceuticals, Medtronic, Abbott, Milestone Pharmaceuticals, and Eagle Pharmaceuticals; and she has received honoraria for speaking from Abbott and Medtronic. Dr Friedman has received research support from the American Heart Association, Boston Scientific, Biosense Webster, Merit Medical, Medtronic, National Institutes of Health, and Abbott; and consulting fees from Abbott, AtriCure, Microport, NI Medical, and Sanofi. Dr Gold serves on a medical advisory board for CVRx and EBR; has received research support to his institution from Boston Scientific, Abbott, and Medtronic; and is a consultant to Boston Scientific, Abbott, and Medtronic. Dr Linde has received research support to her institution from the Swedish Heart-Lung Foundation, Swedish Academy of Science, Roche Diagnostics, AstraZeneca, and Stockholm County Council; and speaker honoraria from Medtronic, Impulse Dynamics, Bayer, Boeringer Ingelheim, Novartis, Vifor Pharma, and Microport. Dr Al-Khatib has received research funding from Medtronic and Boston Scientific through grants to her institution. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)