Evaluation of autonomic control of heart rate in older male patients with chronic obstructive pulmonary disease or chronic heart failure at rest and during sinusal respiratory arrhythmia maneuver

Twenty-eight male volunteers were sub-divided in three groups: ten presented chronic obstructive pulmonary disease (COPD – 69+/-9 years); nine presented chronic heart failure (CHF - 62+/-8 years) and; nine were healthy with 64+/-5 year-old (control). During all experimental protocol, the subjects were monitored at the chest-manubrio lead (MC5) to record the heart rate (HR) beat-to-beat. The ECG and HR were obtained from a one-channel heart monitor (TC 500, ECAFIX, Sao Paulo, SP, Brazil) and processed using an analog-digital converter Lab. PC+ (National Instruments, Co.,Austin, TX, USA), which represents an interface between the heart monitor and a Pentium III microcomputer. The signals were recorded in real time after analog to digital conversion on a beat-to-beat basis using specific software. The three groups’ the electrocardiography signal were obtained on the following conditions: 1) supine position for 15 min; and 2) supine position during the respiratory sinusal arrhythmia (M-RSA)for 4 min. The data were analyzed by the time and the frequency domain. Regarding the M-RSA indexes, the expiratory/inspiratory ratio (E/I) and the inspiratory/expiratory difference (IE difference) were calculated. All evaluations were performed on the same day.