QUANTIFICATION OF ECG LATE POTENTIALS BY WAVELET TRANSFORMATION

Late potentials of preprocessed ECG recordings from patients with sust ained ventricular tachycardia and healthy control subjects are investi gated by the wavelet transformation. The advantages of this non-statio nary signal processing method are discussed in comparison with FFT spe ctrograms of artificial test signals. The energy distribution plots of these wavelet transformed test signals demonstrate the superiority in detection accuracy and frequency resolution compared with the corresp onding spectrograms. For this reason a quantitative discrimination bet ween the two clinical groups of patients and healthy subjects was perf ormed by calculating the scalograms of the wavelet transformed ECG sig nals in the time-frequency plane. The energy in the frequency band of 100-300 Hz during the last time segment of the QRS complex yielded bes t classification results.