title: The Valsalva maneuver in Chagas disease patients without cardiopathy.
abstract: BACKGROUND
  The Valsalva maneuver is a simple and reliable test of parasympathetic heart control that can also be used as a trigger of cardiac arrhythmia. Few studies are available about the Valsalva maneuver in Chagas disease patients without cardiac involvement and their results are contradictory. In a cross-sectional study, we compared Chagas disease patients without cardiac involvement and normal individuals using the Valsalva maneuver in order to study the vagal cardiac control and the occurrence of cardiac arrhythmia in the early phase of Chagas disease.
  
  
  METHODS
  Fifty-nine patients with Chagas disease without cardiac involvement and 37 controls were submitted to a carefully standardized Valsalva maneuver. Cardiac vagal control was assessed by the Valsalva ratio and the occurrence of cardiac arrhythmia was recorded and coded.
  
  
  RESULTS
  The two groups were comparable in terms of left ventricular ejection fraction and left ventricular end-diastolic dimension. When compared to the control group, patients with Chagas disease had significantly lower Valsalva ratios (1.81+/-0.41 versus 2.01+/-0.41, P=0.017) which were not significantly correlated with age, left ventricular function or the presence of radiological esophageal abnormalities. Atrioventricular block (mainly 2nd degree Mobitz type I) occurred exclusively in Chagas disease patients (15,6%, P=0.021) and may indicate an early involvement of the AV node. Premature ventricular contraction was more frequent in Chagas disease patients (16.9% versus 8.1%, P=0.217), although the difference was not statistically significant.
  
  
  CONCLUSIONS
  The Valsalva maneuver is a useful test to detect early vagal dysfunction in Chagas disease patients without cardiac involvement.
authors.affiliation: University Hospital, and Postgraduate Course of Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Enilce
authors.initials: E
authors.lastname: Oliveira
authors.forename: Antonio L P
authors.initials: AL
authors.lastname: Ribeiro
authors.forename: Fernando
authors.initials: F
authors.lastname: Assis Silva
authors.forename: Rosalia M
authors.initials: RM
authors.lastname: Torres
authors.forename: Manoel O C
authors.initials: MO
authors.lastname: Rocha
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology*; D014355:Chagas Disease / Q000150:complications / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D013318:Stroke Volume; D014630:Vagus Nerve / Q000502:physiology; D014636:Valsalva Maneuver