Recurrent Syncope in Patients With Reflex Syncope Treated With Dual-Chamber Pacemakers: Short-Term Associated...

Dual-chamber pacemakers equipped with anti-reflex syncope algorithms are an established therapeutic option for preventing recurrent syncope in selected patients with reflex syncope. However, their efficacy in patients under 40 years old and in non-type 2B syncope remains uncertain and clinical predictors of recurrent syncope post-implantation are not well established.

To identify clinical factors associated with early recurrence of syncope in patients with reflex syncope who received dual-chamber pacemakers with anti-syncope functionality.

This retrospective cohort study included 117 patients (65% female) with reflex syncope confirmed by a positive tilt-table test. All received dual-chamber pacemakers. The primary endpoint was syncope recurrence within 6 months.

Among 117 paced patients, 15 (12.8%) had recurrent syncope by 6 months. In the reduced Cox model, all three prespecified variables independently predicted recurrence: female sex (HR: 5.386; 95% CI: 1.689-17.175; p = 0.004), systolic blood pressure differential between the end of the passive phase and the syncope onset (HR: 1.036; 95% CI: 1.008-1.064; p = 0.011), number of prior syncope episodes (HR: 2.950; 95% CI: 1.565-5.561; p = 0.001). ROC-based cutoffs supported descriptive separation (e.g., ≥ 2.5 prior episodes; ΔSBP ≥ 87.5 mmHg; asystole ≥ 13.5 s), but continuous coding was used for modeling to avoid information loss.

Within 6 months of dual-chamber pacemaker implantation, recurrent syncope was more likely in female sex, a larger systolic blood pressure differential between the end of the passive phase and syncope onset, and greater pre-implantation syncope burdens.