Document Detail

The Valsalva maneuver in Chagas disease patients without cardiopathy.
MedLine Citation:
PMID:  19941031     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: To perform a meta-analysis of studies using the Valsalva ratio (VR) in Chagas disease (ChD) patients without cardiopathy in comparison to control subjects in order to determine if vagal heart modulation is impaired in early forms of ChD. METHODS: The medical literature was systematically searched and reviewed for cross-sectional studies in humans in which the Valsalva maneuver was used to evaluate the autonomic modulation of the heart in ChD patients without cardiopathy. The Hedges g statistic (software Medcalc v. was used to combine the results of all studies through the calculation of the summary standardized mean difference (SMD): the mean VR in controls minus the mean VR in ChD patients, divided by the pooled and adjusted standard deviation. The sample size necessary to detect this SMD with 80% of power was calculated using the G*Power software v.3.0. RESULTS: The meta-analysis included 396 patients in 7 studies. Summary mean VRs were 1.87 +/- 0.39 ms in controls versus 1.74 +/- 0.40 ms in ChD without cardiopathy, leading to a statistically significant summary SMD of -0.310 (95% CI -0.513 to -0.106). Considering the summary SMD of -0.31, an alpha error of 0.05 and a 1:1 ratio of ChD and control patients, the estimated total sample size for a study with 80% power was 330 patients. INTERPRETATION: ChD patients without cardiopathy have reduced VR values compared to healthy controls, indicating early vagal dysfunction. Most previous studies could not detect this impairment due to small study samples and insufficient statistical power.
Antonio L P Ribeiro; Marcos Soares Campos; Leonardo Matos Gomes Baptista; Marcos R de Sousa
Publication Detail:
Type:  Journal Article; Meta-Analysis; Research Support, Non-U.S. Gov't; Review     Date:  2009-11-26
Journal Detail:
Title:  Clinical autonomic research : official journal of the Clinical Autonomic Research Society     Volume:  20     ISSN:  1619-1560     ISO Abbreviation:  Clin. Auton. Res.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-23     Completed Date:  2010-07-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9106549     Medline TA:  Clin Auton Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  79-83     Citation Subset:  IM    
Serviço de Cardiologia, Hospital das Clínicas, Faculdade de Medicina, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190-Campus Saúde, Belo Horizonte, 30130-100, Brazil.
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MeSH Terms
Autonomic Nervous System / physiology
Cardiomyopathies / physiopathology
Case-Control Studies
Chagas Disease / physiopathology*
Cross-Sectional Studies
Middle Aged
Vagus Nerve / physiopathology
Valsalva Maneuver / physiology*

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

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