Cardiac Pacing in Severe Recurrent Reflex Syncope and Tilt-Induced Asystole

Background The benefit of cardiac pacing in patients with severe recurrent reflex syncope and asystole induced by tilt testing has not been established. The usefulness of tilt-table test to select candidates for cardiac pacing is controversial. Methods and results We randomly assigned patients 40 years or older who had at least two episodes of unpredictable severe reflex syncope during the last year and a tilt-induced syncope with an asystolic pause longer than 3 seconds, to receive either an active (pacing ON; 63 patients) or an inactive (pacing OFF; 64 patients) dual-chamber pacemaker with close loop stimulation (CLS). The primary endpoint was the time to first recurrence of syncope. Patients and independent outcomeassessors were blinded to the assigned treatment. After a median follow-up of 11.2 months, syncope occurred in significantly fewer patients in the pacing group than in the control group (10 [16%] vs. 34 [53%]; hazard ratio, 0.23; P=0.00005). The estimated syncope recurrence rate at 1 year was 19% (pacing) and 53% (control); at 2 years, 22% (pacing) and 68% (control).A combined endpoint of syncope or presyncope occurred in significantly fewer patients in the pacing group (23 [37%] vs. 40 [63%]; hazard ratio, 0.44; P=0.002). Minor device-related adverse events were reported in 5 patients (4%). Conclusion In patients 40 years or older, affected by severe recurrent reflex syncope and tiltinduced asystole, dual-chamber pacemaker with CLS is highly effective in reducing recurrences of syncope. Our findings support inclusion of tilt testing as a useful method to select candidates for cardiac pacing.