Vasovagal Syncope International Study - VASIS

Jun 08, 2004
Font Size
A
A
A
Date Published:
01/01/2000
Date Updated:
06/08/2004
Original Posted Date:
06/08/2004
References

Description:

Vasovagal Syncope International Study (VASIS) was a small randomized trial comparing dual-chamber pacemaker implantation versus no pacemaker for the treatment of vasovagal syncope in patients with cardioinhibitory (bradycardic) responses to tilt table testing.

Hypothesis:

Dual chamber (DDI mode) pacing with rate hysteresis will reduce the risk of recurrent syncope compared with not implanting a pacemaker.

Study Design

Study Design:

Patients Screened: ≈1,200
Patients Enrolled: 42
Mean Follow Up: 3.7 ± 2.2 years
Mean Patient Age: Mean: 64 years (pacer), 56 years (no pacer)
Female: 43

Patient Populations:

1) Vasovagal syncope with ≥3 episodes in two years.
2) Most recent syncope within six months of study entry.
3) Age >40 or documented failure of conventional drug therapy if age <40.
4) Cardioinhibitory response on tilt table testing, defined as ventricular rate <40 bpm for >10 seconds or asystole for >3 seconds, with hypotension.

Exclusions:

1) Other cause of syncope known or suspected.
2) Myocardial infarction within six months.
3) New York Heart Association class III or IV heart failure.
4) Severe comorbid disease.

Primary Endpoints:

Recurrent syncope

Secondary Endpoints:

Response to repeat tilt table testing following initial treatment assignment

Drug/Procedures Used:

Patients were randomized to dual-chamber pacemaker implantation or no pacemaker implantation. All pacemakers were programmed to the DDI mode at 80 bpm, with an AV interval of 150 ms and a rate hysteresis of 45 bpm.

Concomitant Medications:

No other specific medical therapies for syncope were permitted in the trial. Investigators discouraged changes in any other vasoactive therapies (e.g., antihypertensive medicines).

Principal Findings:

Recurrent syncope occurred in 1/19 patients (5%) in the pacemaker group versus 14/23 (61%) in the no pacemaker group, p=0.0006. The median time to first recurrent syncope in the no pacemaker group was five months. This effect occurred despite a lack of change on repeat tilt table testing within 15 days after enrollment (tilt positive 59% with pacemaker, 61% without, p=NS).

Interpretation:

Dual chamber pacemakers appear to reduce the frequency of recurrent syncope in highly selected patients with frequent vasovagal syncope and cardioinhibitory responses to tilt table testing. The authors caution that a placebo effect from pacemaker implantation could not be excluded—an effect that appeared to be present in the larger North American Vasovagal Pacemaker Study II.

References:

Sutton R, Brignole M, Menozzi C, et al. Dual-chamber pacing in the treatment of neurally mediated tilt-positive cardioinhibitory syncope: pacemaker versus no therapy: a multicenter randomized study. The Vasovagal Syncope International Study (VASIS) Investigators. Circulation 2000;102:294-9.

Keywords: Syncope, Vasovagal, Placebo Effect, Tilt-Table Test, Hypotension, Pacemaker, Artificial, Heart Arrest, Bradycardia


< Back to Listings