Biventricular pacing improves left ventricular synchrony irrespective of AV-delay in patients with congestive heart failure

Abstract

Background: Biventricular pacing (bivPM) in patients with heart failure results in improved left ventricular performance through resynchronization of systolic myocardial contraction. A prolonged AV-delay improves diastolic left ventricular filling but is associated with increased probability of AV fusion beats that may interfere with resynchronization. The relative influence of these two potentially opposing effects is unknown so far. Aim: To assess the influence of different AV-delays on left ventricular synchrony and left ventricular ejection fraction (EF) using multigated acquisition radionuclide ventriculography (MUGA). Methods: In 12 patients with severe congestive heart failure EF and synchrony was assessed without (noPM) and during bivPM at different AV-delays (80ms, 100ms, 120ms, 140ms, 160ms) with MUGA. Synchrony was defined by the standard deviation in the phase-delay within the left ventricle (LV-SD). This was calculated by use of a phasehistogram and expressed as fraction of a 360°heart cycle. EF was compared to LV-SD at the different AV-delays using Pearson Correlation.