Dual-chamber pacing for vasovagal syncope: A systematic review and meta-analysis of randomized controlled trials

Introduction: Vasovagal syncope (VVS) is the most common cause of transient loss of consciousness and may be recurrent and disabling. Dual-chamber cardiac pacing has been proposed for patients with cardioinhibitory VVS, but randomized trials have yielded inconsistent results, influenced by patient selection and trial blinding. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials evaluating dual-chamber pacing in patients with recurrent cardioinhibitory VVS. PubMed, Embase, and the Cochrane Library were searched from inception to May 2025. Risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using fixed- or random-effects models as appropriate. Prespecified subgroup analyses were performed according to trial blinding status and selection for documented asystolic VVS. Results: Six randomized controlled trials including 429 patients were identified, evaluating rate-drop response, closed-loop stimulation, or DDI pacing. Overall, active pacing significantly reduced syncope recurrence compared with control (RR 0.47; 95% CI 0.27–0.82). The treatment effect was larger and statistically significant in open-label trials (RR 0.22; 95% CI 0.11–0.46), whereas blinded trials showed a non-significant trend toward benefit (RR 0.59; 95% CI 0.32–1.08). In patients with documented asystolic VVS, pacing significantly reduced recurrent syncope (RR 0.35; 95% CI 0.22–0.55), while no significant benefit was observed in patients not selected for asystolic episodes. Conclusion: Dual-chamber pacing was associated with a lower incidence of syncope recurrence across randomized trials in patients with cardioinhibitory vasovagal syncope. However, blinded studies did not demonstrate a statistically significant benefit, and the observed effect appears to be largely influenced by open-label trial designs.