Cardiac Resynchronization Therapy for Various Systemic Ventricular Morphologies in Patients With Congenital Heart Disease

Background: Cardiac resynchronization therapy (CRT) can result in functional improvement and reduced mortality in patients with medically refractory heart failure. Although CRT is reportedly effective in patients with congenital heart disease (CHD), it is still controversial in patients who have systemic right ventricle. Methods and Results: Twenty CHD patients treated with CRT since 2006 were divided into 3 groups based on systemic ventricular (sysV) morphology (7 with left ventricle [sLV], 7 with right ventricle [sRV], and 6 with unbalanced 2 ventricles as a single-ventricular physiology [sBV]). The acute effects of CRT on hemodynamics and sysV function before device implantation was retrospectively evaluated and the chronic (>= 6 months) effects of CRT on late outcomes was assessed. In our CHD populations, sysV volume index was reduced from 139 +/- 41 to 118 +/- 33 ml/m(2) (P=0.04) after CRT, and there was significant improvement in B-type natriuretic peptide levels (from 341 +/- 384 to 160 +/- 152 pg/ml, P=0.01) and New York Heart Association (NYHA) functional class (from 2.1 +/- 0.6 to 1.8 +/- 0.7, P=0.02) on a late outcome. The sRV group did not show a late sysV volume reduction despite significant QRS shortening, and an increase of sysV peak dP/dt in the acute study differed from that of other groups. Conclusions: CRT improves late hemodynamic and functional status in sLV and sBV CHD patients with a dyssynchronized sysV. However, an acute CRT effect cannot guarantee long-term benefit in sRV patients.