Title: Biventricular pacing in patients with bradycardia and normal ejection fraction
Yu et al (N Engl J Med 2009;361:2123-2134; PMID: 19915220) evaluated whether biventricular (BiV) pacing is superior to right ventricular apical (RVA) pacing in preventing deterioration of left ventricular (LV) systolic function and cardiac remodeling in patients with bradycardia and a normal ejection fraction (EF). In this prospective, double-blind, multicenter study, 177 patients with implantation of a BiV pacemaker were randomized to BiV pacing (89 patients) or RVA pacing (88 patients). The primary end points were the LVEF and LV end-systolic volume. At 12 months, the mean LVEF was significantly lower with RVA pacing than in the BiV pacing (54.8_/-9.1% vs. 62.2_/-7.0%, P_0.001).The LV end-systolic volume was significantly higher in the RVA pacing group than in the BiV group (35.7_/-16.3 ml vs. 27.6_/-10.4 ml, P_0.001). The authors conclude that in patients with normal LVEF, RVA pacing resulted in adverse LV remodeling and in a reduction in the LVEF. These effects were prevented by biventricular pacing.
