Aims: We aimed to investigate whether biventricular (BiV) pacing minimizes left ventricular (LV) dyssynchrony and preserves LV ejection fraction (LVEF) as compared with standard dual-chamber DDD(R) pacing in consecutive patients with high-grade atrio-ventricular (AV) block.
Methods and results: Fifty patients were randomized to DDD(R) pacing or BiV pacing. LVEF was measured using three-dimensional echocardiography. Tissue-Doppler imaging was used to quantify LV dyssynchrony in terms of number of segments with delayed longitudinal contraction (DLC). LVEF was not different between groups after 12 months (P = 0.18). In the DDD(R) group LVEF decreased significantly from 59.7(57.4-61.4)% at baseline to 57.2(52.1-60.6)% at 12 months of follow-up (P = 0.03), whereas LVEF remained unchanged in the BiV group [58.9(47.1-61.7)% at baseline vs. 60.1(55.2-63.3)% after 12 months (P = 0.15)]. Dyssynchrony was more prominent in the DDD(R) group than in the BiV group at baseline (2.2 +/- 2.2 vs. 1.4 +/- 1.3 segments with DLC per patient, P = 0.10); and at 12 month follow-up (1.8 +/- 1.9 vs. 0.8 +/- 0.9 segments with DLC per patient, P = 0.02). NT-proBNP was unchanged in the DDD(R) group during follow-up (122 +/- 178 pmol/L vs. 91 +/- 166 pmol/L, NS) but decreased significantly in the BiV-group (from 198 +/- 505 pmol/L to 86 +/- 95 pmol/L after 12 months, P = 0.02).
Conclusion: BiV pacing minimizes LV dyssynchrony, preserves LV function, and reduces NT-proBNP in contrast to DDD(R) pacing in patients with high-grade AV block.