Discrimination between ventricular tachycardia and ventricular fibrillation using the continuous wavelet transform

An efficient and precise discrimination algorithm for the two malign cardiac rhythms, namely VT and VF rhythms, is of great importance in the design of AEDs. The method put forward in the present work exploits the regularity observed in the coefficients of the continuous wavelet transform (CWT) of a VT segment. In a preliminary stage the wavelet analyzing function yielding the best results is selected. The ECG records are then divided in segments of 4.8 seconds where the CWT coefficients are calculated for those scales considered significant. The separation of the peaks in the time evolution of the coefficients is proportional to the cardiac frequency and the amplitude of the peaks is more uniform as the rhythm becomes more regular. The discrimination parameters selected for the algorithm are based on the dispersion of the position and the amplitude of those peaks. The accuracy achieved, 94.74%, improves the results obtained by previously reported methods.