Echocardiographic assessment of ventricular contraction and synchrony in children with isolated complete atrioventricular block and epicardial pacing: Implications of interventricular mechanical delay.

AIMS: To assess the correlations between interventricular mechanical delay (IVMD) and cardiac function in children with isolated complete atrioventricular block and epicardial pacing.

METHODS AND RESULTS: We enrolled 13 children (six boys) with an epicardial dual-chamber pacemaker due to isolated complete or advanced atrioventricular block. The patients were 9.8 (range, 6.8-15.3) years old, and none had symptomatic heart failure at the follow-up visit. Ventricular pacing sites, which remained the same for 7.2 (1.6-12.3) years, were the left ventricle (LV) in two patients, right ventricle (RV) in four patients, and both ventricles in seven patients. IVMD was ≤40 ms in six patients (short IVMD group) and >40 ms in seven patients (long IVMD group). Compared with the long IVMD group, the short IVMD group was associated with better LV longitudinal strain (-20% [-24% to -18%] vs -16% [-20% to -13%], P < .05). The short IVMD group had superior LV mechanical synchrony than the long IVMD group (septal to lateral delay of the time to peak longitudinal strain 15 [-16-78] ms vs 78 [13-93] ms, P < .05; standard deviation of the time to peak radial strain 13 [9-34] ms vs 35 [18-64] ms, P < .05).

CONCLUSION: In children with epicardial pacing at LV, RV, or both ventricles, a left-sided contraction delay was associated with poorer LV contraction and impaired LV synchrony. IVMD will help to stratify patients during follow-up.