Short- and mid-term clinical effectiveness of cardiac resynchronization therapy optimized AV/VV delay dynamically for patients with congestive heart failure

AIM: To observe the short-term and mid-term clinical effectiveness of cardiac resynchronization therapy (CRT) optimized AV/VV delay dynamically for patients with congestive heart failure (CHF). METHODS: Twelve patients with refractory heart failure received CRT device implantation. Pacing parameters were tested and AV/VV interval was optimized by the guidance of echocardiography during the follow-up period. The effectiveness of CRT was evaluated in terms of echocardiography, tissue Doppler, ECG and BNP during the follow-up period. RESULTS: The best optimized AV delay was between 120 msec and 180 msec (158±19)msec and the best optimized VV delay was between 4 msec and 28 msec (16±7)msec. The heart function classification, quality of life, 6-min hall walking distance was significantly increased (257±23)m to (344±21)m. QRS interval decreased from (136±17)msec to (109±12)msec (P<0.05). With significant reduction of left ventricular end-diastolic (LVEDD) ［(71±10)mm vs.(54±4), P<0.05］, the left ventricular ejection fraction (LVEF) increased ［(0.308±0.022) vs.(0.531±0.085), P<0.01］. Plasma BNP decreased from (876±415)ng/L to (70±28)ng/L (P<0.05) and the intra- and inter-ventricular asynchrony indexes were significantly improved. CONCLUSION: Dynamically optimized AV/VV delay of the pacemaker parameters enhances the short- and mid-term effects of CRT.