A method for the ventricular late potentials detection and characterisation using wavelets

In this paper we present a method for the ventricular late potentials (VLP) characterisation using the discrete wavelet transform with the Daubechies wavelets and the Newland´s (1993) harmonic and musical wavelets. The method is based on a wavelet multiresolution scheme where the energy content of the beat-by-beat ST and the TP segments of the high resolution electrocardiogram (HR-ECG) are compared at different resolutions. An objective figure, the factor of normality is generated for ready clinical use. These results were compared to the ones obtained with the application of the spectrogram, and the Choi-Williams transform, using the spectro-temporal Mapping, for the VLP´s study. A high resolution system for the acquisition of the high resolution electrocardiogram (HR-ECG) has been set up, with amplitude and group delay error less than 1% for which a multirate technique was used. In this way we could guarantee that our data were adequate to be submitted to the time-frequency and time-scale (wavelet) analysis. The factor of normality generated by the multiresolution scheme proved to be more sensitive, in our study cases, but the method requires further clinical testing