Cardiovascular outcomes with atrial-based pacing compared with ventricular pacing: meta-analysis of randomized trials, using individual patient data.

BACKGROUND Several randomized trials have compared atrial-based (dual-chamber or atrial) pacing with ventricular pacing in patients with bradycardia. No trial has shown a mortality reduction, and only 1 small trial suggested a reduction in stroke. The goal of this review was to determine whether atrial-based pacing prevents major cardiovascular events. METHODS AND RESULTS A systematic review was performed of publications since 1980. For inclusion, trials had to compare an atrial-based with a ventricular-based pacing mode; use a randomized, controlled, parallel design; and have data on mortality, stroke, heart failure, or atrial fibrillation. Individual patient data were obtained from 5 of the 8 identified studies, representing 95% of patients in the 8 trials, and a total of 35 000 patient-years of follow-up. There was no significant heterogeneity among the results of the individual trials. There was no significant reduction in mortality (hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.87 to 1.03; P=0.19) or heart failure (HR, 0.89; 95% CI, 0.77 to 1.03; P=0.15) with atrial-based pacing. There was a significant reduction in atrial fibrillation (HR, 0.80; 95% CI, 0.72 to 0.89; P=0.00003) and a reduction in stroke that was of borderline significance (HR, 0.81; 95% CI, 0.67 to 0.99; P=0.035). There was no convincing evidence that any patient subgroup received special benefit from atrial-based pacing. CONCLUSIONS Compared with ventricular pacing, the use of atrial-based pacing does not improve survival or reduce heart failure or cardiovascular death. However, atrial-based pacing reduces the incidence of atrial fibrillation and may modestly reduce stroke.