Multicenter Study of Survival Benefit of Cardiac Resynchronization Therapy in Pediatric and Congenital Heart Disease

Abstract

Background: Evidence for the efficacy of cardiac resynchronization therapy (CRT) in pediatric and congenital heart disease (CHD) has been limited to surrogate outcomes. Objectives: This study aimed to assess the impact of CRT upon the risk of transplantation or death in a retrospective, high-risk, controlled cohort at 5 quaternary referral centers. Methods: Both CRT patients and control patients were <21 years of age or had CHD; had systemic ventricular ejection fraction <45%; symptomatic heart failure; and significant electrical dyssynchrony (QRS duration z score >3 or single-site ventricular pacing >40%) at enrollment. Patients with CRT were matched with control patients via 1:1 propensity score matching. CRT patients were enrolled at CRT implantation; control patients were enrolled at the outpatient clinical encounter where inclusion criteria were first met. The primary endpoint was transplantation or death. Results: In total, 324 control patients and 167 CRT recipients were identified. Mean follow-up was 4.2 ± 3.7 years. Upon propensity score matching, 139 closely matched pairs were identified (20 baseline indices). Of the 139 matched pairs, 52 (37.0%) control patients and 31 (22.0%) CRT recipients reached the primary endpoint. On both unadjusted and multivariable Cox regression analysis, the risk reduction associated with CRT for the primary endpoint was significant (HR: 0.40; 95% CI: 0.25-0.64; P < 0.001; and HR: 0.44; 95% CI: 0.28-0.71; P = 0.001, respectively). On longitudinal assessment, the CRT group had significantly improved systemic ventricular ejection fraction (P < 0.001) and shorter QRS duration (P = 0.015), sustained to 5 years. Conclusions: In pediatric and CHD patients with symptomatic systolic heart failure and electrical dyssynchrony, CRT was associated with improved heart transplantation-free survival.