RESUMO
BACKGROUND: Autonomic regulation analysis is useful in risk stratification of ventricular tachycardia and sudden cardiac death in chronic heart failure (CHF). Heart rate variability (HRV) reflects the condition of autonomic regulation. For analyzing the autonomic control the whole cardiovascular system has to be considered. Therefore, the aim of our study was to assess the influence of peripheral arterial disease (PAD) on the autonomic regulation. METHODS: In 53 men (age: 67 +/- 11 years) from the cardiovascular unit we compared standard HRV parameters in 27 with (ankle brachial index, ABI < 0.9) and 26 patients without (ABI >0.9) PAD as well as with 12 healthy subjects as reference. High-resolution electrocardiograms were recorded over 30 minutes under resting conditions. Pulse wave velocity as well as ABI was estimated using the vascular screening system VASERA. RESULTS: In cardiac patients with PAD, we found both significant differences in linear and nonlinear HRV parameters. Higher increase of low-than high-frequency components indicated higher elevated sympathetic than vagal activation. Altered autonomic control can be interpreted as a compensatory mechanism for diminished vascular arteriolar vasodilator capacity in PAD. To maintain the arterial blood pressure, an elevated setpoint of sympathovagal balance is required. CONCLUSIONS: Our data indicate PAD alters the HRV in cardiovascular patients. PAD should be considered in the assessment of cardiac autonomic regulation especially in risk stratification.