Cardiac resynchronization therapy with or without defibrillation in patients with non-ischemic cardiomyopathy: a systematic review and meta-analysis

Abstract Introduction Cardiac resynchronization treatment (CRT) is a significant medical achievement for patients with heart failure and electrical desynchrony to relieve symptoms, reduce hospitalization, and increase survival, both with and without implantable cardioverter-defibrillator therapy. However, the value of defibrillator therapy in addition to CRT in patients with non-ischemic cardiomyopathy (NICM) who are eligible for CRT remains unclear. Objective Compare the outcomes of patients with NICM and heart failure who received CRT with implantable cardioverter-defibrillator (CRT-D) against CRT-pacemaker only (CRT-P). Methods A literature search from inception through January 2023 was conducted in PubMed and Cochrane Central Register of Controlled Trials for all studies reporting outcomes of CRT-D versus CRT-P in CRT-eligible patients with NICM. Studies reporting non-stratified outcomes, including patients with ischemic cardiomyopathy, were excluded. The primary endpoint of interest was all-cause mortality. Secondary outcomes included device complications. A random-effects model was used. Results Of a total of 1976 potential citations, the search yielded 9 citations that met our inclusion criteria. Ten studies were included, one randomized clinical trial and nine observational studies, providing 11064 CRT-eligible patients with NICM (7459 CRT-D implantation and 1275 with CRT-P). Our meta-analysis revealed a significantly lower all-cause mortality (pooled OR, 0.85; 95% CI [0.75, 0.97], P = 0.02; I ²= 31%), albeit with moderate heterogeneity. Additionally, regarding device complications, only one study reported these outcomes with no significant difference (HR 0.82 [95% CI, 0.29–2.20]). Conclusions Our meta-analysis suggests that the addition of defibrillator therapy significantly reduced all-cause mortality in CRT-eligible patients with NICM.