Inter- and intra-ventricular dyssynchrony in the systemic right ventricle is a surrogate marker of major cardiac events in mildly symptomatic patients.

The aim of the study was to evaluate systemic right ventricular (RV) dyssynchrony in patients with congenitally corrected transposition of the great arteries (CCTGA) and transposition of the great arteries (TGA) with New York Heart Association functional class (NYHA FC) < III. We used cardiac magnetic resonance (CMR) to evaluate the dyssynchrony and assessed whether RV dyssynchrony can be predictive of major cardiac events in their early stages in these patients. We enrolled 71 consecutive, NYHA FC < III patients with systemic RV who underwent CMR between April 1995 and December 2016. We measured intra- and inter-ventricular dyssynchrony using a feature-tracking method of cine magnetic resonance imaging. The predictors of major cardiac events were analyzed using the Cox hazard analysis. The data from 36 patients with CCTGA and 35 patients with TGA after an atrial switch were analyzed. Seven (19.4%) patients with CCTGA and 6 (17.1%) patients with TGA showed a QRS duration of ≥ 130 ms. There were significant intra- and inter-dyssynchrony in the systemic RV groups, compared to healthy controls. The average follow-up period was 5.1 ± 3.9 years. From among patients with CCTGA, 9 (25.0%) had major cardiac events. The parameters including NYHA FC, indexed RV volume, longitudinal early diastolic strain rate, and intra- and inter-ventricular dyssynchrony were predictive of major cardiac events. From among patients with TGA, 12 (34.3%) had major cardiac events. Age, NYHA FC, QRS duration, RV volume, RV mass index, LV volume, global longitudinal/circumferential strain and intraventricular dyssynchrony, were all predictive of major cardiac events. Systemic RV in NYHA FC < III patients with CCTGA and TGA, have obvious intra- and inter-dyssynchrony, suggesting ineffective wall motion and potential RV dysfunction. Intraventricular dyssynchrony can be an adjunct predictor of major cardiac events in mildly symptomatic patients with both CCTGA and TGA.