Empiric pacing in unexplained syncope and bifascicular block: A systematic review and meta-analysis

Patients with unexplained syncope and bifascicular block (BFB) are at risk for intermittent high-grade atrioventricular block. Management strategies include empiric pacemaker implantation (EPI) or other alternative approaches (implantable cardiac monitor or electrophysiology study), but the optimal strategy remains uncertain.

To evaluate the efficacy and safety of EPI compared to alternative approaches in patients with unexplained syncope and BFB.

We systematically reviewed six studies (2 randomized controlled trials and 4 cohort studies; n = 601) comparing EPI versus alternative strategies in patients with BFB and unexplained syncope. Primary outcomes were predefined as syncope and bradycardia. Secondary outcomes were bradyarrhythmia, cardiovascular death, and device complications. Risk ratios (RR) were synthesized with a random-effects model.

EPI significantly reduced recurrence of syncope (RR 0.48 [0.35, 0.65], p = 3.4E-6), bradycardia (RR 0.06 [0.016, 0.26], p = 7.6E-5), and bradyarrhythmia (RR 0.64 [0.43, 0.96], p = 0.034). Notably, neither device-related complications (RR 1.30 [1.00-1.71], p = 0.06) nor cardiovascular death (RR 0.98 [0.82-1.16], p = 0.82) were significantly increased with EPI.

In patients with unexplained syncope and BFB, EPI significantly reduces recurrent syncope and bradycardia without increasing device-related complications or cardiovascular mortality. These findings support the efficacy and safety of empiric pacing as a reasonable management strategy in this high-risk population.