Evaluation of heart rate variability in time — Frequency domain

Signal recorded by electrocardiogram (ECG) is one of the most important biosignals giving information about state of living organism. The ECG, for example carries information about instantaneous heart frequency, based on heart rate variability. Changes in heart rate from beat to beat gives valuable diagnostic information about the autonomous nervous system status and the heart itself. The paper describes a method of analysis of heart rate variability in frequency and time-frequency domain. In order to compare alternative results four basic methods were chosen, namely: Welch, Burg, Lomb-Scargle method and Wavelet transform.