A randomized, double-blind, placebo-controlled study of permanent cardiac pacing for the treatment of recurrent tilt-induced vasovagal syncope. The vasovagal syncope and pacing trial (SYNPACE)

Abstract

Recently, some studies revealed the efficacy of pacemaker implantation in decreasing recurrences in patients with vasovagal syncope. As these studies were not blinded or placebo-controlled, the benefits observed might have been due to a bias in the assessment of outcomes or to a placebo effect of the pacemaker. We performed a randomized, double-blind, placebo-controlled study in order to ascertain if pacing therapy reduces the risk of syncope relapse. Twenty-nine patients (53±16 years; 19 women) with severe recurrent tilt-induced vasovagal syncope (median 12 syncopes in the lifetime) and 1 syncopal relapse after head-up tilt testing underwent implantation of a pacemaker, and were randomized to pacemaker ON or to pacemaker OFF. During a median of 715 days of follow-up, 8 (50%) patients randomized to pacemaker ON had recurrence of syncope compared to 5 (38%) of patients randomized to pacemaker OFF (p=n.s.); the median time to first syncope was longer in the pacemaker ON than in pacemaker OFF group, although not significantly so (97 [38–144] vs 20 [4–302] days; p=0.38). There was also no significant difference in the subgroups of patients who had had a mixed response and in those who had had an asystolic response during head-up tilt testing. Our data were unable to show a superiority of active pacing versus inactive pacing in preventing syncopal recurrence in patients with severe recurrent tilt-induced vasovagal syncope.