title: Association between endothelial function and autonomic modulation in patients with Chagas disease.
abstract: BACKGROUND
  Under homeostatic condition, the autonomic nervous system (ANS), through the release of vasoconstrictor neurotransmitters, and the endothelium, through the release of vasodilating substances, interact to maintain blood vessel tone. However, the association between those two systems in patients with Chagas disease in its indeterminate phase (IChD) has not been studied.
  
  
  OBJECTIVE
  To assess the association between autonomic modulation parameters and endothelial function in patients with IChD.
  
  
  METHODS
  Thirteen patients with IChD (59.2 ± 11.23 years) and no risk factors for cardiovascular disease were assessed for autonomic modulation by using the blood pressure oscillometric method (Finapress) and the heart rate variability technique (HRV) in the frequency domain. Endothelial function was assessed by use of the brachial artery flow-mediated dilation (FMD) method with high-resolution ultrasound images.
  
  
  RESULTS
  In the dorsal decubitus position, correlation of FMD was observed with normalized high-frequency (r = 0.78; p = 0.007) and low-frequency spectral components (r = 0.68; p = 0.01), as well as with sympathovagal balance (r = -0.78; p = 0.004).
  
  
  CONCLUSIONS
  Our study indicates the existence of a relationship between the changes in autonomic modulation and endothelial function in patients with IChD.
authors.affiliation: Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, RS, Brasil. truccolo@cpovo.net
authors.forename: Adriana Barni
authors.initials: AB
authors.lastname: Truccolo
authors.forename: Thiago
authors.initials: T
authors.lastname: Dipp
authors.forename: Bruna
authors.initials: B
authors.lastname: Eibel
authors.forename: Rodrigo Antonini
authors.initials: RA
authors.lastname: Ribeiro
authors.forename: Karina Rabello
authors.initials: KR
authors.lastname: Casali
authors.forename: Maria Claudia
authors.initials: MC
authors.lastname: Irigoyen
authors.forename: Iseu
authors.initials: I
authors.lastname: Gus
authors.forename: Lucia Campos
authors.initials: LC
authors.lastname: Pellanda
authors.forename: Rodrigo Della Meã
authors.initials: RD
authors.lastname: Plentz
mesh_terms: D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D014355:Chagas Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D012039:Regional Blood Flow / Q000502:physiology; D018709:Statistics, Nonparametric; D018615:Ultrasonography, Doppler, Color