Document Detail


Second Vasovagal Pacemaker Study (VPS II): rationale, design, results, and implications for practice and future clinical trials.
MedLine Citation:
PMID:  15071266     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Vasovagal syncope causes substantial morbidity. Various medications have been studied with goals of reducing event-rates and improving quality of life. Results have been mixed, with few drugs demonstrating benefit. Bradycardia usually accompanies vasovagal syncope during positive tilt table tests, and is recorded in up to 50% of clinical syncopal spells documented on electrocardiographic loop recorders. These findings form the rationale for studies of the effectiveness of pacing in preventing vasovagal syncope. Three historically controlled trials of permanent pacing showed that 80-90% of patients had a marked symptomatic improvement, with 90-95% reductions in the number of expected syncopal spells. Subsequently three open-label trials randomized a total of 189 patients evenly to medical therapy or pacemakers in trials that used the proportion of patients with recurrent syncope as the primary outcome. They showed relative risk reductions of 80-87% in the paced patients. However these early studies were not blinded, raising concern about the possible role of a significant placebo effect. This issue was addressed in the recent Second Vasovagal Pacemaker Study (VPS II), in which 100 patients received pacemakers. They then were randomized to pacing with rate drop sensing, or sensing without pacing. The cumulative risk of syncope at 6 months was 40% for the control group and 31% for the actively paced group. The relative risk reduction in time to syncope with pacing was 30% (1 p = 0.14). The AHA/ACC guidelines about pacing and vasovagal syncope should be reassessed. Future clinical trials of therapies for vasovagal syncope should be randomized and placebo-controlled.
Authors:
Robert Sheldon; Stuart Connolly;
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Cardiac electrophysiology review     Volume:  7     ISSN:  1385-2264     ISO Abbreviation:  Card Electrophysiol Rev     Publication Date:  2003 Dec 
Date Detail:
Created Date:  2004-04-08     Completed Date:  2004-08-26     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9708907     Medline TA:  Card Electrophysiol Rev     Country:  United States    
Other Details:
Languages:  eng     Pagination:  411-5     Citation Subset:  IM    
Affiliation:
Cardiovascular Research Group, University of Calgary, Calgary, Alberta, Canada. sheldon@ucalgary.ca
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MeSH Terms
Descriptor/Qualifier:
Bradycardia / prevention & control
Cardiac Pacing, Artificial* / methods
Humans
Multicenter Studies as Topic
Pacemaker, Artificial
Randomized Controlled Trials as Topic
Recurrence
Research Design
Syncope, Vasovagal / prevention & control*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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