Abstract 18035: Left Ventricular Remodeling After Long-term Right Ventricular Pacing is Predicted by Electrical and Mechanical Dyssynchrony, but not Pacing Site
Introduction: Long-term right ventricular apical (RVA) pacing has been shown to cause adverse left ventricular (LV) remodeling and clinical outcomes. We investigated the predictors of LV remodeling after long-term RV pacing.
Methods: One hundred and two patients (54M, mean age 73.5±13.0, 50 RV septal and 52 RVA pacing) undergoing pacemaker implantation for atrio-ventricular block from January 2003 to June 2008 were studied. LV remodeling was assessed by echocardiography performed at least 18 months after implantation. Clinical outcomes including all-cause mortality, heart failure, ischaemic stroke and atrial fibrillation were analyzed. Electrical dyssynchrony (Edys) was measured by QRS duration during pacing. Mechanical dyssynchrony (Mdys) was measured by standard deviation of time to peak systolic velocities of 12 LV segments from echocardiography during pacing.
Results: There was no difference in all clinical outcomes between RV septal and RVA pacing groups (Mean follow-up 38.4±17.7months). With multivariate stepwise regression, only Edys (p=0.002) and Mdys (p=0.016) but not pacing site (RVA or RV septal), were independent predictors for LV remodeling indices, namely LV ejection fraction(LVEF), end-systolic volume (LVESV) and end-diastolic volume (LVEDV). The presence of 2 positive criteria (Edys<150ms, Mdys<33ms) compared to 1 or no positive criteria, resulted in significantly less adverse LV remodeling: LVESV(20.1±7.8vs33.7±16.9vs42.5±21.6ml, p=0.003), LVEDV(51±12.9vs75.5±25vs86.9±26.9ml, p<0.001) and LVEF(61.3±7.1vs56.1±8.3vs52.6±10.9%, p=0.02).
Conclusions: Edys and Mdys were independent predictors for LV remodeling after long-term RV pacing. They may be targets for pacing site optimization.
- © 2010 by American Heart Association, Inc.