Abstract
Patients with congenitally corrected transposition of the great arteries (CCTGA) are predisposed to atrioventricular block, pacing-induced cardiomyopathy, and right ventricular (RV) failure. Although biventricular cardiac resynchronization therapy (CRT) and conduction system pacing (CSP) have been described, RV failure may persist. Three cases of CCTGA with intrinsic RV electrical delay are presented where conventional CSP targeting the His bundle or proximal left bundle branches resulted in incomplete electrical resynchronization. With CSP-optimized CRT, there was greater electrical synchrony, followed by marked clinical improvement. In select patients with CCTGA, CSP-optimized CRT may be of clinical benefit.