Outcomes of conduction system and right ventricular pacing in bradyarrhythmia indications: A systematic review and meta-analysis of propensity-score matched and randomized studies

Background Evidence supporting the use of conduction system pacing (CSP) in bradycardia is currently predominantly based on observational data. We performed a meta-analysis of recent propensity-score matched (PSM) studies and randomized controlled trials (RCTs) evaluating outcomes of CSP and right ventricular pacing (RVP) in bradycardia indications. Methods We systematically searched three databases for eligible studies. Risk ratios (RRs) and mean differences (MDs) with their 95% confidence intervals (CI) were pooled using a random-effects model. Subgroup analyses of RCTs were performed for key outcomes. Results Fifteen studies (8 RCTs, 7 PSM) comprising 6,064 patients were included. Compared to RVP, CSP significantly reduced heart failure hospitalizations (RR:0.31; 95% CI:0.21–0.46; p < 0.001) and the need for cardiac resynchronization therapy (CRT) upgrades (RR:0.31; 95% CI:0.12–0.78; p = 0.01), while modestly improving left ventricular ejection fraction (MD:3.98%; 95% CI:2.22–5.74; p < 0.001) and resulting in narrower QRS durations (MD:-27.3 ms; 95% CI:-35.9 to -18.6; p < 0.001). These findings were consistent in sub-analyses of RCTs. CSP was associated with reduction of all-cause mortality in the overall analysis (RR:0.51; 95% CI:0.34–0.78; p = 0.002), but not in the RCT and PSM subgroups. No significant differences between groups were observed for cardiovascular mortality (RR:0.49; 95% CI:0.23–1.04; p = 0.06), procedural complications, or atrial fibrillation. CSP was associated with longer procedural and fluoroscopy times. Conclusion CSP significantly reduces the risk of heart failure hospitalizations and the need for CRT upgrades compared to RVP in patients with bradycardia indications. Ongoing, large-scale RCTs are needed to verify the effect of CSP on mortality and its long-term safety.