The North American Vasovagal Pacemaker Study - VPS


This was a randomized trial done to evaluate whether pacemaker therapy controls symptoms in the setting of severe vasovagal syncope.


In patients with recurrent vasovagal syncope due primarily to relative bradycardia, the implantation of a permanent, dual chamber pacemaker with rate-drop response would decrease the recurrent episodes of syncope.

Study Design

Study Design:

Patients Enrolled: 54
Female: 72

Patient Populations:

Patients with at least 6 lifetime episodes of syncope and with tilt-table test that induced syncope or presyncope, as well as relative bradycardia were enrolled.


Patients with other causes for loss of consciousness such as ventricular tachycardia, complete heart block, postural hypotension, carotid hypersensitivity syndrome or seizers were excluded. Patients were excluded with significant valvular, conduction, coronary or myocardial abnormality. Patients with prior pacemaker implantation, contraindication to inserion of permanent pacemaker, or a major chronic noncardiovascular disease were exluded.

Primary Endpoints:

The primary endpoint was first recurrence of syncope

Secondary Endpoints:

Patients tracked presyncopal episodes in a diary and graded symptoms on a 10-point scale.

Drug/Procedures Used:

Patients were randomized to permanent pacemaker (Medtronic Thera DR with rate drop sensing) implantation or usual therapy.

Principal Findings:

The study was terminated early after interim analysis demonstrated a large treatment effect. The primary endpoint of first recurrence of syncope was less frequent in those who underwent pacemaker implantation compared to those who did not (70% versus 22%; p<0.05). The relative risk reduction was 85.4% (95% confidence interval, 59.7% to 94.7%).


1.Pacing & Clinical Electrophysiology 1997;20:844-8. Study design 2. Connolly SJ, Sheldon R, Roberts RS, Gent M. The North American Vasovagal Pacemaker Study (VPS). A randomized trial of permanent cardiac pacing for the prevention of vasovagal syncope. J Am Coll Cardiol 1999 Jan;33(1):16-20.

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices

Keywords: Risk, Recurrence, Syncope, Vasovagal, Tilt-Table Test, Pacemaker, Artificial, Confidence Intervals, Bradycardia

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