Ventricular pacing in single ventricles-A bad combination.

Background: Chronic ventricular pacing (VP) is associated with systolic dysfunction in a subset of pediatric patients with heart block and structurally normal hearts. The effect of chronic VP in congenital heart disease is less well understood, specifically in the single-ventricle (SV) population.

Objective: To determine the longitudinal effect of VP in SV patients.

Methods: SV patients with heart block and dual-chamber pacemakers requiring >50% VP were compared with nonpaced (controls) SV patients matched for age, sex, and SV morphology. Patients were excluded if a prepacing echocardiogram was not available. Echocardiogram and clinical parameters were compared at baseline (prepacing) and at last follow-up in the paced group, and in controls when they were at ages similar to those of their paced-group matches.

Results: Twenty-two paced and 53 control patients from 2 institutions were followed for similar durations (6.6±5 years vs 7.6±7.6 years; P = .59). There was no difference between groups regarding baseline ventricular function or the presence of moderate-to-severe atrioventricular valvar regurgitation (AVVR). Paced patients were more likely to develop moderate-to-severe systolic dysfunction (68% vs 15%; P < .01) and AVVR (55% vs 8%; P < .001) and require heart failure medications (65% vs 21%; P < .001). Chronic VP was also associated with a higher risk of transplantation or death (odds ratio, 4.9; 95% confidence interval, 1.05-22.7; P = .04).

Conclusions: SV patients requiring chronic VP are at higher risk of developing moderate-to-severe ventricular dysfunction and AVVR with an increased risk of death or transplantation compared with controls. New strategies to either limit VP or improve synchronization in this vulnerable population is imperative.