title: Heart rate recovery in asymptomatic patients with Chagas disease.
abstract: BACKGROUND
  Chagas disease patients with right bundle-branch block (RBBB) have diverse clinical presentation and prognosis, depending on left ventricular (LV) function. Autonomic disorder can be an early marker of heart involvement. The heart rate recovery (HRR) after exercise may identify autonomic dysfunction, with impact on therapeutic strategies. This study was designed to assess the HRR after symptom-limited exercise testing in asymptomatic Chagas disease patients with RBBB without ventricular dysfunction compared to patients with indeterminate form of Chagas disease and healthy controls.
  
  
  METHODS
  One hundred and forty-nine subjects divided into 3 groups were included. A control group was comprised of healthy individuals; group 1 included patients in the indeterminate form of Chagas disease; and group 2 included patients with complete RBBB with or without left anterior hemiblock, and normal ventricular systolic function. A symptom-limited exercise test was performed and heart rate (HR) response to exercise was assessed. HRR was defined as the difference between HR at peak exercise and 1 min following test termination.
  
  
  RESULTS
  There were no differences in heart-rate profile during exercise between healthy individuals and patients in indeterminate form, whereas patients with RBBB had more prevalence of chronotropic incompetence, lower exercise capacity and lower HRR compared with patients in indeterminate form and controls. A delayed decrease in the HR after exercise was found in 17 patients (15%), 9% in indeterminate form and 24% with RBBB, associated with older age, worse functional capacity, impaired chronotropic response, and ventricular arrhythmias during both exercise and recovery. By multivariable analysis, the independent predictors of a delayed decrease in the HRR were age (odds ratio [OR] 1.11; 95% confidence interval [CI] 1.03 to 1.21; p = 0.010) and presence of RBBB (OR 3.97; 95% CI 1.05 to 15.01; p = 0.042).
  
  
  CONCLUSIONS
  A small proportion (15%) of asymptomatic Chagas patients had attenuated HRR after exercise, being more prevalent in patients with RBBB compared with patients in indeterminate form and controls.
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Maria Clara Noman
authors: MC
authors: de Alencar
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Manoel Otávio da Costa
authors: MO
authors: Rocha
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Márcia Maria de Oliveira
authors: MM
authors: Lima
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Henrique Silveira
authors: HS
authors: Costa
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Giovane Rodrigo
authors: GR
authors: Sousa
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Renata de Carvalho Bicalho
authors: Rde C
authors: Carneiro
authors: School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Guilherme Canabrava Rodrigues
authors: GC
authors: Silva
authors: School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Fernando Vieira
authors: FV
authors: Brandão
authors: University of Minnesota Medical School, Minneapolis, Minnesota, United States of America.
authors: Lucas Jordan
authors: LJ
authors: Kreuser
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Antonio Luiz Pinho
authors: AL
authors: Ribeiro
authors: Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Maria Carmo Pereira
authors: MC
authors: Nunes
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D058070:Asymptomatic Diseases; D002037:Bundle-Branch Block / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D016022:Case-Control Studies; D014355:Chagas Disease / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D004562:Electrocardiography; D015444:Exercise; D005080:Exercise Test / Q000706:statistics & numerical data*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D014349:Trypanosoma cruzi / Q000502:physiology; D016277:Ventricular Function, Left