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.
Conclusion: 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.