Left ventricular volumes and systolic function after long-term right ventricular pacing may be predicted by paced QRS duration, but not pacing site.

Background: Long-term right ventricular apical (RVA) pacing causes adverse left ventricular (LV) remodelling and clinical outcomes.

Methods: Forty-one patients (19 men, mean age 70.9±14.2, 23 right ventricular septal and 18 RVA pacing) underwent pacemaker implantation for atrioventricular block. LV volumes and left ventricular ejection fraction (LVEF) were assessed by echocardiography 39.3±17.2 months after implantation. Predictors of left ventricular systolic volume (LVESV), left ventricular diastolic volume (LVEDV) and LVEF were analysed.

Results: No difference was found between RVA pacing and right ventricular septal pacing groups in LVESV (40.6±22.6 vs 33±14.4ml; p=0.199), LVEDV (88.2±31.2 vs 73.7±23.9ml; p=0.102) and LVEF (56.1±8.6 vs 56±6.6%; p=0.996). With multivariate stepwise regression, only pQRSd and renal impairment independently predicted LVESV (β=0.522, 95% CI: 0.242-0.802; p=0.001 and β=40.3, 95% CI: 17.6-62.9; p=0.001 respectively), LVEDV (β=0.786, 95% CI: 0.338-1.235; p=0.001 and β=42.8, 95% CI: 6.6-79; p=0.022 respectively) and LVEF (β=-0.161, 95% CI: -0.283 to -0.04; p=0.011 and β=-14.8, 95% CI: -24.6 to -5.0; p=0.004 respectively).

Conclusions: pQRSd and renal impairment, but not pacing site or baseline LVEF, may be predictors for LV volumes and systolic function after long-term RV pacing. pQRSd may be target for pacing site optimisation.