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

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.

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.

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.

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.