VPS-II

Second Vasovagal Pacemaker Study

Patient / Population Intervention / Exposure Comparison Outcome

In 100 patients with recurrent severe vasovagal syncope who all received a dual-chamber pacemaker, active dual-chamber pacing did not significantly reduce recurrence of syncope within 6 months compared with the pacemaker programmed to sensing only.

100

Design

Double-blind RCT (pacing on vs sensing only)

Endpoint

Time to first recurrence of syncope

Relevance

ResultCumulative 6-month risk 31 % vs 40 %; relative risk reduction 30 % (95 % CI −33 % to 63 %; one-sided p=0.14). Complications included 7 lead dislodgements, 1 tamponade and 1 generator infection.

Connolly SJ, Sheldon R, Thorpe KE, et al. JAMA. 2003;289(17):2224-2229. 10.1001/jama.289.17.2224

Discussion & critique

Underpowered and short, and it enrolled tilt-positive patients without documented spontaneous asystole, so a real effect in the truly cardioinhibitory subgroup could have been missed. Its enduring value is methodological: by implanting every patient and randomising only the programming, it showed the benefit reported by earlier unblinded pacing trials was largely a placebo effect of surgery.