Systematic review and meta-analysis comparing cardiac resynchronization therapy with versus without defibrillation in patients with non-ischemic cardiomyopathy

Abstract

Abstract Background Cardiac resynchronization therapy (CRT) stands as a notable medical breakthrough for individuals with heart failure and electrical desynchrony. This intervention aims to alleviate symptoms, diminish hospitalization rates, and enhance overall survival, both in conjunction with and without implantable cardioverter-defibrillator (ICD) therapy. Despite these advancements, the role of defibrillator therapy in addition with CRT for patients with non-ischemic cardiomyopathy (NICM) remains a topic of debate. Objective To assess and compare the outcomes of individuals diagnosed with NICM who have underwent CRT with implantable cardioverter-defibrillator (CRT-D) against those who received CRT with a pacemaker only (CRT-P). Methods We conducted a systematic search of PubMed, Embase and Cochrane database during August 2023 for studies comparing CRT-P and CRT-D in patients with nonischemic cardiomyopathy. Results Thirteen studies, including two randomized clinical trials, were incorporated, with a total of 61,326 patients providing 16,446 pooled death events (9,108 in CRT-D and 7,338 in CRT-P). The meta-analysis revealed that CRT-D was associated with a significantly lower risk of all-cause mortality compared to CRT-P (pooled HR 0.74; 95% CI: 0.62-0.88; I2=84%). Subgroup analysis focusing on propensity score-matched studies yielded consistent findings (pooled HR 0.82; 95% CI: 0.77-0.87; I² = 0%, P<0.001). However, subgroup analysis for patients older than 75 years suggested no statistically significant difference in mortality risk within this specific age group (pooled HR 0.96; 95% CI: 0.811-1.15; I² = 39%, P<0.001). Regarding the secondary endpoint of cardiovascular mortality, no significant risk reduction with CRT-D was observed (pooled HR 0.70; 95% CI: 0.49-1.01; I² = 92%), albeit with high heterogeneity. Conclusion Our study suggests that the addition of defibrillator therapy significantly reduces all-cause mortality in CRT-eligible patients with NICM, although results were not observed for patients older than 75 years.All-cause MortalityPatients older 75 years old