Wavelets extrema representation for QRS-T cancellation and P wave detection

P wave detection requires a robust QRS-T cancellation method. Some interesting algorithms have been proposed for beat-to-beat QRS-T cancellation. Previous studies have shown that adaptive methods lead to a good cancellation of QRS-T interval which generally guaranty the performances of P wave detection. However, adaptive methods suffer from the non-stationary behavior of the ECG signals and particularly the beat-to-beat morphology changes of the QRS. We present a new approach for two ECG channels QRS-T cancellation based on dyadic wavelets transform. The method is insensitive to QRS morphology changes and performs well in presence of ectopic beats, transient artifacts, baseline drifts and isolated P waves. Our approach allows the P wave to be enhanced better than methods recently proposed.