title: Heart Rate Variability Correlates to Functional Aerobic Impairment in Hemodialysis Patients.
abstract: BACKGROUND
  Autonomic dysfunction (AD) is highly prevalent in hemodialysis (HD) patients and has been implicated in their increased risk of cardiovascular mortality.
  
  
  OBJECTIVE
  To correlate heart rate variability (HRV) during exercise treadmill test (ETT) with the values obtained when measuring functional aerobic impairment (FAI) in HD patients and controls.
  
  
  METHODS
  Cross-sectional study involving HD patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, 24-hour Holter, and ETT were performed. A symptom-limited ramp treadmill protocol with active recovery was employed. Heart rate variability was evaluated in time domain at exercise and recovery periods.
  
  
  RESULTS
  Forty-one HD patients and 41 controls concluded the study. HD patients had higher FAI and lower HRV than controls (p<0.001 for both). A correlation was found between exercise HRV (SDNN) and FAI in both groups. This association was independent of age, sex, smoking, body mass index, diabetes, and clonidine or beta-blocker use, but not of hemoglobin levels.
  
  
  CONCLUSIONS
  No association was found between FAI and HRV on 24-hour Holter or at the recovery period of ETT. Of note, exercise HRV was inversely correlated with FAI in HD patients and controls.
authors.affiliation: Department of Cardiology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: Maria Angela Magalhães de Queiroz
authors.initials: MA
authors.lastname: Carreira
authors.affiliation: Department of Cardiology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: André Barros
authors.initials: AB
authors.lastname: Nogueira
authors.affiliation: Department of Cardiology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: Felipe Montes
authors.initials: FM
authors.lastname: Pena
authors.affiliation: Department of Cardiology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: Marcio Galindo
authors.initials: MG
authors.lastname: Kiuchi
authors.affiliation: Department of Cardiology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: Ronaldo Campos
authors.initials: RC
authors.lastname: Rodrigues
authors.affiliation: Department of Cardiology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: Rodrigo da Rocha
authors.initials: Rda R
authors.lastname: Rodrigues
authors.affiliation: Department of Nephrology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: Jorge Paulo Strogoff de
authors.initials: JP
authors.lastname: Matos
authors.affiliation: Department of Nephrology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil.
authors.forename: Jocemir Ronaldo
authors.initials: JR
authors.lastname: Lugon
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000209:etiology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D012016:Reference Values; D006435:Renal Dialysis; D012307:Risk Factors; D018709:Statistics, Nonparametric; D013997:Time Factors