Some basic experiments toward the applications of hilbert transform to the electrocardiogram

The application of the Hilbert transform (HT) to ECG analysis requires a priori knowledge of the phase spectrum of the original signal. The authors analyzed ECG recordings from ten healthy subjects in the Politecnico Milano-Ca Granda VCG/ECG database. Different epochs and leads were considered. The results confirm the known results for the 100-Hz significant band. In this band the standard deviation of the phase spectra is much less than 90°. This permits the use of HT to represent ECG signals. The statistics of the computed HT evidence the better stability of this transform in comparison to the original signal.