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Vasovagal Pacemaker Study II - VPS II
Description:
The goal of the trial was to evaluate the use of dual-chamber pacing for reducing the risk of recurrent syncope in patients with vasovagal syncope.
Study Design
Study Design:
Patients Enrolled: 100
Mean Follow Up: Six months
Mean Patient Age: Mean age 49 years
Female: 60
Patient Populations:
Age >18 years; history of recurrent vasovagal syncope with ≥6 episodes of syncope ever, or ≥3 episodes in the prior two years; positive head-up tilt table test with a heart rate x blood pressure product of <6000/min x mm Hg
Exclusions:
Syncope due to any other cause; important valvular, coronary artery, or myocardial disease; an electrocardiographic abnormality; or any major noncardiovascular disease
Primary Endpoints:
Syncope, defined as a transient loss of consciousness with prompt spontaneous recovery
Drug/Procedures Used:
All patients in the trial were implanted with a dual-chamber pacemaker. Patients were randomized to receive dual-chamber pacing (DDD; n=48) with rate drop response or to have only sensing without pacing (n=52).
Concomitant Medications:
At baseline: beta-blockers (48%); fludrocortisone (19%); selective serotonin reuptake inhibitor (23% in sensing only group and 13% in pacing group)
During follow-up: beta-blockers (12% in sensing only group and 19% in pacing group); fludrocortisone (10% and 2%, respectively); selective serotonin reuptake inhibitor (12% and 13%, respectively)
Principal Findings:
There were significantly more women randomized to the dual-chamber pacing group (72.9% vs. 48.1%), but other baseline characteristics were well balanced. Median number of syncope events in the prior year was four in each group, with the time from most recent event one month in each group. Mean duration of tilt table test was 30 minutes.
Syncope episodes occurred in 42% of the sensing only group compared with 33% of the pacing group (relative risk reduction [RRR] 30.2%, log-rank p=0.14). In an analysis excluding the one patient in the pacing group who had the pacemaker removed, the RRR was 35% (p=0.10). Self-reported presyncope occurred in nearly all study patients (94% in sensing only group and 96% in pacing group, p>0.99).
There was one major pacemaker complication in each group (one pericardial tamponade in the pacing group and one infection requiring reimplantation in the sensing only group). Additionally, seven patients had lead dislodgement or needed repositioning.
Interpretation:
Among patients with vasovagal syncope, use of dual-chamber pacing was not associated with a reduction in the primary endpoint of recurrent syncope compared with no pacing.
Earlier studies, including VPS I, demonstrated a reduction in recurrent syncope episodes compared with usual care, but these studies were not blinded, as only patients randomized to the pacing group were implanted with a pacemaker. The present study is the first double-blind, randomized trial of pacemaker therapy in syncope patients. Given the lack of demonstrated benefit and the not infrequent complications associated with the pacemaker implantation (whether it was pacing or not), the authors concluded pacemaker therapy should not be recommended as first-line therapy for patients with vasovagal syncope.
References:
Connolly SJ, Sheldon R, Thorpe KE, et al. Pacemaker therapy for prevention of syncope in patients with recurrent severe vasovagal syncope: Second Vasovagal Pacemaker Study (VPS II): a randomized trial. JAMA 2003;289:2224-9.
Keywords: Syncope, Vasovagal, Risk Reduction Behavior, Replantation, Tilt-Table Test, Blood Pressure, Pacemaker, Artificial, Heart Rate, Cardiac Tamponade
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