Use of the Wavelet Transform for Time-Frequency Localization of Late Potentials

Several methods have been developped to obtain relevant information from signal-averaged high-resolution ECG signals. Time-domain and frequency-domain analysis in separate have not proved to give sufficient diagnostic power in recent years. Detection of high-frequency low-amplitude signals such as late potentials needs combined time-frequency analysis. Several problems arise in the attempt to use STFT for this purpose. The way of solving some of them leads to diminishing or eliminating the most significant part of the signal- the nonstationarity. This paper examines the Wavelet Transform to obtain time-frequency distributions of enhanced time resolution for higher-frequency signal components in the detection of late potentials. We employeed the wavelet of Morlet with three sets of analysing waves distributed evenly in the frequency range of interest.