The Second Vasovagal Pacemaker Study (VPSII)

Abstract

The Second Vasovagal Pacemaker Study (VPSII): A double‐blind randomized controlled trial of pacemaker therapy for the prevention of syncope in patients with recurrent severe vasovagal syncope. Three previous small randomized trials have reported that pacemaker therapy is very beneficial for patients with severe recurrent vasovagal syncope. However these trials were not double blind and were thus at risk of bias in assessment of outcomes and of a ‘placebo‐effect’ of surgery. To determine if pacing therapy reduces the risk of syncope in patients with vasovagal syncope. A double‐blind randomized trial of pacemaker therapy was performed. After implantation of a dual chamber pacemaker, 100 patients from 15 centres were randomized, double blind, to receive dual chamber pacing (DDD) with rate drop response or to have only sensing with no pacing (ODO). Patients were followed for up to 6 months and the primary outcome of the study was time to first recurrence of syncope. Results: Patients were well matched as to baseline characteristics. In the year prior to randomization patients had had a median of 4 episodes of syncope. No patients were lost to follow up. Of the patients randomized to ODO, 22 of 52 (42%) had recurrent syncope within 6 months, compared to 16 of 48 (33%) of the patients in the DDD group. The cumulative risk of syncope at 6 months was 40% (95% confidence interval 25%, 52%) for the ODO group and was 31% (95% confidence interval 17%, 43%) for the DDD group. The relative risk reduction in time to syncope with DDD pacing was 30% (95% confidence interval −33%, 63%, p = 0.14 one‐sided). Lead dislodgement or repositioning occurred in 7 patients, one patient had vein thrombosis and another had pericardial tamponade leading to removal of the pacemaker system. One patient had infection involving the pacemaker generator. Conclusions: This double blind randomized trial does not confirm the results of earlier smaller unblinded randomized trials. Because of the weak evidence of efficacy of pacemaker therapy and the risk of complications, pacemaker therapy should not be recommended as first line therapy for patients with recurrent vasovagal syncope.