Função autonômica cardíaca e nível de atividade física de pacientes com doença arterial coronariana

Abstract

The aim of this study was to investigate the relation between the autonomic modulation of heart rate (HR) and the level of habitual physical activity (HPA) in patients with coronary artery disease (CAD). This is a cross-sectional study with a sample of 26 men (age 59.6 ± 4.2) with CAD diagnosed for a mean time of 16±3 months, divided into two groups, users (GB, n=12) and non-users of beta-blockers (GSB, n=14). To evaluate the autonomic modulation, the analysis of heart rate variability (HRV) was performed from the registration of rest RR intervals for 15 minutes in the supine posture. Baecke questionnaire was applied to verify the level of HPA. The HPA total score correlated positively with indices of HRV respectively for GB and GSB: square root of the mean squared differences of successive normal RR intervals (r=0.499; P=0.039 and r=0.612; P=0.010), power of high frequency component (r=0.675; P=0.008 and r=0.470; P=0.045), Shannon entropy (r=0.594; P=0.021 and r=0.453; P=0.042) and normalized conditional entropy (r=0.805; P=0.001 and r=0.559; P=0.019), patterns of two different variations (r=0.872; P<0.001 and r=0.630; P=0.008), and correlated negatively with power of low frequency component (r=-0.675; P=0.008 and r=-0.470; P=0.045), low/high frequency ratio (r=-0.675; P=0.008 and r=-0.466; P=0.047) and no variation pattern (r=-0.782; P=0.001 and r=-0.684; P=0.004). In patients with CAD, high level of HPA was related to increased parasympathetic and reduced sympathetic modulation to the heart at rest, suggesting that higher levels of physical activity are related to better cardiovascular autonomic modulation in this population.