Amplitude of ECG potentials varies on a beat-to-beat basis. This variability can be seen in different parts of ECG cycles and is usually periodic in nature. In our study we present a new method allowing analysis of such type of variability. It investigates the distribution of variability power in time and frequency domains (spectrotemporal maps). A new feature of the method is its ability to attenuate errors in amplitude variability measurements coming from RT interval alterations. We present also examples of spectro-temporal maps obtained in healthy subjects, surgically denervated patients after heart transplantation and patients with coronary artery disease.

Keywords: Spectral analysis, beat-by-beat analysis, amplitude variability, ecg