VENTRICULAR LATE POTENTIALS CHARACTERIZATION IN TIME-FREQUENCY DOMAINBY MEANS OF A WAVELET TRANSFORM

The main transforms of Cohen's class allow signal representation simul taneously in time and frequency domains. Wavelet transforms make it po ssible to link the temporal window width to the analyzing frequency an d leads to a ''modified wavelet transform'' which improves resolution both in time and frequency. A simulation study illustrates the artifac ts of every time-frequency representation (TFR) on pure sinusoids and gives performance evaluation of the different methods when searching a sinusoid embedded in a QRS complex. Analyses of real signals from hea lthy and pathological subjects confirm the simulation results and comp lete the characterization of ventricular late potentials (VLP) yet det ected by signal averaging.