Impact of Cardiac Resynchronization Therapy on Heart Transplant-Free Survival in Pediatric and Congenital Heart Disease Patients.

Background - Cardiac resynchronization therapy (CRT) studies in pediatric and/or congenital heart disease (CHD) patients have shown an improvement in ejection fraction and heart failure symptoms. However, a survival benefit of CRT in this population has not been established. This study aimed to evaluate the impact of CRT upon heart transplant-free survival in pediatric and CHD patients, using a propensity score-matched analysis. Methods - This single-center study compared CRT patients (implant date 2004-2017) and controls, matched by 1:1 propensity-score matching (PSM) using 21 comprehensive baseline indices for risk stratification. CRT patients were <21 years or had CHD; had systemic ventricular ejection fraction <;45%; symptomatic heart failure; and had significant electrical dyssynchrony, all prior to CRT implant. Controls were screened from non-selective imaging and ECG databases. Controls were retrospectively enrolled when they achieved the same inclusion criteria at an outpatient clinical encounter, within the same time period. Results - Of 133 patients who received CRT during the study period, 84 met all study inclusion criteria. 133 controls met all criteria at an outpatient encounter. Following PSM, 63 matched CRT-control pairs were identified with no significant difference between groups across all baseline indices. Heart transplant or death occurred in 12 (19%) PSM-CRT subjects and 37 (59%) PSM-controls with a median follow-up of 2.7 years (quartiles 0.8-6.1 years). CRT was associated with markedly reduced risk of heart transplant or death (hazard ratio 0.24 [95% CI 0.12-0.46], p<0.001). There was no CRT procedural mortality and one system infection at 54 months post-implant. Conclusions - In pediatric and CHD patients with symptomatic systolic heart failure and electrical dyssynchrony, CRT was associated with improved heart transplant-free survival.