Clinical outcomes with biventricular versus right ventricular pacing in patients with atrioventricular conduction defects.

There have been increasing concerns about the unexpected effects of right ventricular (RV) pacing. We aimed to systematically evaluate the effect of biventricular (BiV) versus RV pacing on clinical events in patients with impaired AV conduction. We searched PubMed, EMBASE, and Cochrane Library for studies comparing BiV pacing with RV pacing in patients with AV block, through April 2017. We selected randomized controlled trials (RCTs) reporting data on mortality, hospitalization for heart failure (HF), and/or 6-min walk distance (6MWD). A total of 12 RCTs were finally included. Pooled analysis suggested that BiV pacing was associated with a significantly reduced all-cause mortality in contrast to RV pacing (risk ratio (RR) = 0.77, 95% confidence interval (CI) 0.62 to 0.95, I2 = 9.6%). BiV pacing, compared with RV pacing, significantly reduced the rate of HF hospitalization (RR = 0.74, 95% CI 0.59 to 0.93, I2 = 10.1%). Sensitivity analyses by excluding studies with AV nodal ablation showed that BiV pacing still had a lower mortality and non-significant reduced HF hospitalization. Patients in BiV and RV pacing mode had a similar 6WMD at follow-up (mean difference = 4.99 m, 95% CI - 11.34 to 21.33 m, I2 = 0%). Meta-regression analysis showed that the effect size of all-cause mortality or HF hospitalization was not significantly associated with mean LVEF value at baseline. In patients with impaired AV conduction that need frequent ventricular pacing, BiV pacing was associated with reduced mortality and hospitalization for HF, compared with traditional RV pacing mode.