title: Autonomic control of heart rate in patients with chronic cardiorespiratory disease and in healthy participants at rest and during a respiratory sinus arrhythmia maneuver.
abstract: OBJECTIVE
  To evaluate the autonomic modulation of heart rate (HR) at rest in the supine position and during a respiratory sinus arrhythmia maneuver (M-RSA) among participants with chronic obstructive pulmonary disease (COPD) or with chronic heart failure (CHF).
  
  
  METHODS
  Twenty-eight men were divided into three groups: ten with COPD, aged 69+/-9 years; nine with CHF, aged 62+/-8 years; and nine healthy participants aged 64+/-5 years (controls). At rest, the R-R interval of the electrocardiographic signal was obtained in the following situations: 1) 15 min in the supine position; and 2) 4 min during M-RSA in the supine position. The data were analyzed in the time domain (RMSSD and SDNN indices) and the frequency domain (LFab and HFab). During M-RSA, the expiratory/inspiratory ratio (E/I) and the inspiratory/expiratory difference (IE) were calculated.
  
  
  RESULTS
  The main findings showed that the CHF patients presented lower RMSSD (12.2+/-2.6 vs. 20.4+/-6.5), LFab (99.2+/-72.7 vs. 305.3+/-208.9) and HFab (53.4+/-29.9 vs. 178.9+/-113.1), compared with the controls. The LFab band was significantly lower in the COPD group than in the controls (133.8+/-145.5 vs. 305.3+/-208.9). Additionally, both CHF patients and COPD patients showed lower E/I ratios (1.1+/-0.06 vs. 1.2+/-0.1 and 1.1+/-0.03 vs. 1.2+/-0.1) and IE values (7.0+/-3.5 vs. 12.7+/-0.1 and 4.9+/-1.6 vs. 12.7+/-0.1), respectively, compared with the controls during M-RSA.
  
  
  CONCLUSIONS
  The results from this study suggest that both COPD and CHF have a negative impact on the autonomic control of heart rate. Article registered on the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number: ACTRN12609000467235.
authors.affiliation: Universidade Federal de São Carlos, São Carlos, SP, Brasil.
authors.forename: Michel S
authors.initials: MS
authors.lastname: Reis
authors.forename: Ana P
authors.initials: AP
authors.lastname: Deus
authors.forename: Rodrigo P
authors.initials: RP
authors.lastname: Simões
authors.forename: Isabela A V
authors.initials: IA
authors.lastname: Aniceto
authors.forename: Aparecida M
authors.initials: AM
authors.lastname: Catai
authors.forename: Audrey
authors.initials: A
authors.lastname: Borghi-Silva
mesh_terms: D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002908:Chronic Disease; D006333:Heart Failure / Q000503:physiopathology*; D006334:Heart Function Tests / Q000379:methods; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012146:Rest; D016683:Supine Position