Evidence for the efficacy of pacing

The vasovagal response is a notable but transient dysfunction of the autonomic nervous system. The most readily quantitative responses are vasodepression (arterial blood pressure fall) and cardioinhibition (heart rate fall). Cardiac pacing offers the possibility specifically to target the latter. Evidence to support the use of pacing in this setting has recently gained additional weight with the publication of the vasovagal pacemaker study.1 Patients with recurrent episodes of vasovagal syncope (more than six each year) were randomised to receive or not receive a permanent dual chamber pacemaker. This important study indicated a clear benefit for pacing in those with vasovagal syncope selected on the basis of positive tilt test with bradycardia. In those allocated to receive a pacemaker there was a notable extension in the time to recurrence of syncope with a relative risk reduction of 85.4%. This treatment effect remained despite adjusting for the observed baseline differences between the paced and non-paced groups (relative risk reduction of 90.8%).

Even before the …