Evaluating the response to cardiac resynchronization therapy performed with a new ventricular morphology-based strategy for congenital heart disease.

backgroundIn cardiac resynchronization therapy (CRT) for patients with congenital heart disease (CHD) and a ventricular morphology other than a systemic left ventricle (LV), we previously proposed pacing sites that are different from those used for a systemic LV. The leads should be placed laterally on opposite sides of both ventricles in patients with short-axis dyssynchrony and a single ventricular physiology with two ventricles, whereas they should be placed at the farthest sites along the longitudinal direction in the right ventricle (RV) in patients with long-axis dyssynchrony of the RV. Moreover, in patients with interventricular dyssynchrony and a biventricular physiology with a systemic RV, they should be placed at sites that both ventricles can contract simultaneously. We retrospectively investigated 27 consecutive procedures in 24 patients with CHD who underwent CRT to evaluate the effectiveness of a new ventricular morphology-based CRT strategy. The responder rate was 63% (17/27). The reasons for a non-response to CRT in 10 cases were as follows: non-optimal lead positions during CRT, 4; no systemic ventricular conduction delay or heart failure symptoms before the CRT, 5; short follow-up periods after the CRT, 2; and an extremely dilated systemic RV, 1. The responder rate became 88% (14/16), after excluding the procedures without a ventricular conduction delay or heart failure symptoms and those with non-optimal lead positions. This new strategy for CRT can provide favorable results for CHD patients with a systemic ventricular conduction delay and heart failure.