2400Early and late effects of cardiac resynchronization therapy in adult congenital heart disease

Background There are limited data regarding cardiac resynchronization therapy (CRT) in adult congenital heart disease (ACHD). Purpose We aimed to assess early and late outcomes of CRT amongst patients with ACHD. Methods We retrospectively studied ACHD patients receiving CRT (2004–2017). Clinical and echocardiographic data were analyzed at baseline, early (1.8±0.8 years) and late (4.7±0.8 years) follow-up after CRT. Results Fifty-four ACHD patients (median age 46 years, range 18–73 years, 74% male) had CRT (biventricular paced >90%) and were followed for 5.7±3.0 years. Thirty-nine (72%) patients had a systemic left ventricle (LV). Underlying cardiac anatomy included left ventricular outflow tract lesions (n=17; 32%), tetralogy of Fallot (n=11; 20%), right ventricular outflow tract lesions (n=5; 9%), atrioventricular septal defects (n=5; 9%) and atrial septal defect with right aortic arch (n=1; 2%). Fifteen (28%) patients had a systemic right ventricle (RV): 13 (24%) with congenitally corrected transposition of great arteries, and 2 (4%) with transposition of the great arteries after Mustard repair. Compared to baseline, CRT was associated with significant improvement at early follow-up in NYHA functional class, QRS duration, cardiothoracic ratio, left and right atrial volume index (P<0.05 for all) in the overall population; improvement in NYHA class was sustained at late follow-up. Amongst patients with a systemic LV, there was significant increase in LV ejection fraction and reduction in LV end-systolic volume at early and late follow up (P<0.05 for both). There is trend in improvement of RV fractional area change in the patients with a systemic RV but not met statistical significance (P=0.070). Findings were summarized in Figure 1. Eleven patients died and 2 had heart transplantation unrelated to systemic ventricular morphology. Thirty-five (65%) patients responded positively to CRT but only baseline QRS duration was a predictor of the positive response. Conclusion CRT results in sustained improvement in functional class, systemic LV size and function. QRS duration but not QRS morphology was a predictor of the positive response seen at early follow-up in 2/3 of ACHD patients.