Sequential biventricular pacing improves regional contractility, longitudinal function and dyssynchrony in patients with heart failure and prolonged QRS

AIMS: Biventricular pacing (BiP) is an effective treatment in systolic heart failure (HF) patients with prolonged QRS. However, approximately 35% of the patients receiving BiP are classified as non-responders. The aim of this study is to evaluate the acute effects of VV-optimization on systolic heart function. METHODS: Twenty-one HF patients aged 72 (46-88) years, QRS 154 (120-190) ms, were studied with echocardiography, Tissue Doppler Imaging (TDI) and 3D-echo the first day after receiving a BiP device. TDI was performed; during simultaneous pacing (LV-lead pacing 4 ms before the RV-lead) and during sequential pacing (LV 20 and 40 ms before RV and RV 20 and 40 ms before LV-lead pacing). Systolic heart function was studied by tissue tracking (TT) for longitudinal function and systolic maximal velocity (SMV) for regional contractility and signs of dyssynchrony assessed by time-delays standard deviation of aortic valve opening to SMV, AVO-SMV/SD and tissue synchronization imaging (TSI). RESULTS: The TT mean value preoperatively was 4.2 +/- 1.5 and increased at simultaneous pacing to 5.0 +/- 1.2 mm (p < 0.05), and at best VV-interval to 5.4 +/- 1.2 (p < 0.001). Simultaneous pacing achieved better TT distance compared with preoperative in 16 patients (76%). However, it was still higher after VV-optimization in 12 patients 57%. Corresponding figures for SMV were 3.0 +/- 0.7, 3.5 +/- 0.8 (p < 0,01), and 3.6 +/- 0.8 (p < 0.001). Also dyssynchrony improved. CONCLUSIONS: VV-optimization in the acute phase improves systolic heart function more than simultaneous BiP pacing. Long-term effects should be evaluated in prospective randomized trials.