109-07: Echocardiographic effects of pulmonary right ventricular resynchronization in congenital heart disease Free

Introduction: Right ventricular (RV) electromechanical dyssynchrony may contribute to long-term pulmonary RV dysfunction in patients after surgery for congenital heart disease. We sought to evaluate immediate changes in RV mechanics after RV resynchronization (RV-CRT).

Methods: 22 consecutive patients aged median 11.7 years with tetralogy of Fallot (N = 14), pulmonary atresia (N = 6), double outlet RV (N = 1) and arterial trunc (N = 1), resp., were echocardiographically studied following surgical RV revalvulation. RV-CRT was applied in the presence of complete right bundle branch block (RBBB) by atrial-triggered RV free wall pacing in complete fusion with spontaneous activation using temporary postoperative pacing wires.

Results: RV-CRT carried significant decrease in QRS duration (P < 0.001) along with elimination of the RBBB pattern, increase in RV filling time (P = 0.009), pulmonary artery velocity time integral (P = 0.015) and RV max. +dP/dt as estimated from the tricuspid regurgitation jet (P = 0.011). RV mechanical synchrony improved: Septal to lateral RV mechanical delay decreased from median 65 to 28 ms (P < 0.001). RV internal stretch fraction (ISF) reflecting the ratio of myocardial stretching and contraction during systole diminished from mean (SD) 0.18 (0.09) to 0.09 (0.04) (P = 0.001, Figure). The q-RV interval at the pacing site (mean 77.1 % of baseline QRS duration) confirmed pacing from a late-activated RV area.

Conclusions: RV-CRT carried multiple positive effects on RV mechanics including improvement in filling, systolic function and mechanical synchrony and efficiency. (Supported by Ministry of Health of the Czech Republic, grant nr. 15-28029A)

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