It is well known that heart rate (HR) fluctuates in time and that this variation is closely related to changes in the neural activity to the heart.1,2 Therefore, HR variability represents a noninvasive parameter for studying the autonomic control to the heart. Recently, it has been shown that HR variability is a powerful independent prognostic factor in patients with coronary artery disease3 and a low HR variability count has been found to be related to sudden death.4 Spectrum analysis of HR may provide further information, since HR variability possesses 2 major components that have been shown to relate to different patterns of neural control to the heart.5,6 Patients with congestive heart failure (CHF) have a complex abnormality of the autonomic control to the heart7 that also affects some HR characteristics.8 These abnormalities may be determined either by a selective reduction of the vagal outflow to the heart or by a more complex abnormality. This investigation was undertaken to evaluate the components of HR variability in normal persons and patients with CHF, and their 24-hour behavior.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine