OBJECTIVETo assess the effect of A-V, V-V delay optimization on cardiac function and clinical improvement in patients with refractory heart failure underwent cardiac resynchronization therapy (CRT).

METHODThirty-two patients with chronic heart failure received CRT and cardiac function was measured at 7 days, 3 months and 6 months post CRT before and after A-V and V-V delay optimizations.

RESULTSA-V delay optimization was initiated in 28, 10 and 6 cases at 7th day, 3rd month and 6th month after CRT. V-V delay optimization was performed in 29, 6 and 5 cases at 7th day, 3rd month and 6th month after CRT. Ts-SD, LVEF, VTI and E/Em were significantly improved after CRT compared to pre-CRT (P < 0.01, P < 0.05, P < 0.05, P < 0.05; respectively). Compared to pre-optimization, the indexes of ventricular synchronization were significantly improved (P < 0.05) while indexes of cardiac function remained unchanged post optimization at 7th day after CRT. The indexes of ventricular synchronization post optimization were similar at 7th, 3rd and 6th months after CRT (P > 0.05). LVEF and diastolic filling time were significantly increased after 6 months CRT post A-V, V-V delay optimization (P < 0.01).

CONCLUSIONA-V, V-V delay optimization at 7th day after CRT can significantly improve ventricular synchronization and is associated with further improved cardiac function 6 months after CRT.