title: Detection of autonomic dysfunction in hemodialysis patients using the exercise treadmill test: the role of the chronotropic index, heart rate recovery, and R-R variability.
abstract: OBJECTIVE
  To evaluate the ability of different parameters of exercise treadmill test to detect autonomic dysfunction in hemodialysis patients.
  
  
  METHODS
  Cross-sectional study involving hemodialysis patients and a control group. Clinical examination, blood sampling, echocardiogram, 24-hour Holter, and exercise treadmill test were performed. A ramp treadmill protocol symptom-limited with active recovery was employed.
  
  
  RESULTS
  Forty-one hemodialysis patients and 41 controls concluded the study. There was significant difference between hemodialysis patients and controls in autonomic function parameters in 24h-Holter and exercise treadmill test. Probability of having autonomic dysfunction in hemodialysis patients compared to controls was 29.7 at the exercise treadmill test and 13.0 in the 24-hour Holter. Chronotropic index, heart rate recovery at the 1st min, and SDNN at exercise were used to develop an autonomic dysfunction score to grade autonomic dysfunction, in which, 83% of hemodialysis patients reached a scoring ≥2 in contrast to 20% of controls. Hemodialysis was independently associated with either altered chronotropic index or autonomic dysfunction scoring ≥2 in every tested model (OR=50.1, P=0.003; and OR=270.9, P=0.002, respectively, model 5).
  
  
  CONCLUSIONS
  The exercise treadmill test was feasible and useful to diagnose of the autonomic dysfunction in hemodialysis patients. Chronotropic index and autonomic dysfunction scoring ≥2 were the most effective parameters to differentiate between hemodialysis patients and controls suggesting that these variables portrays the best ability to detect autonomic dysfunction in this setting.
authors.affiliation: Department of Medicine, Cardiology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: Maria Angela M Q
authors.initials: MA
authors.lastname: Carreira
authors.affiliation: Department of Medicine, Cardiology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: André B
authors.initials: AB
authors.lastname: Nogueira
authors.affiliation: Department of Medicine, Cardiology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: Felipe M
authors.initials: FM
authors.lastname: Pena
authors.affiliation: Department of Medicine, Nephrology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: Marcio G
authors.initials: MG
authors.lastname: Kiuchi
authors.affiliation: Department of Medicine, Cardiology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: Ronaldo C
authors.initials: RC
authors.lastname: Rodrigues
authors.affiliation: Department of Medicine, Cardiology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil; Department of Medicine, Nephrology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: Rodrigo R
authors.initials: RR
authors.lastname: Rodrigues
authors.affiliation: Department of Medicine, Nephrology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: Jorge P S
authors.initials: JP
authors.lastname: Matos
authors.affiliation: Department of Medicine, Nephrology Division, Medical School, Universidade Federal Fluminense, Rio de Janeiro, Brazil.
authors.forename: Jocemir R
authors.initials: JR
authors.lastname: Lugon
mesh_terms: D001342:Autonomic Nervous System Diseases / Q000503:physiopathology*; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D006435:Renal Dialysis