A new method for automatic delineation of ECG fiducial points based on the Phasor Transform

The present work introduces a new ECG delineator, based on the Phasor Transform, which is characterized by its robustness, low computational cost and mathematical simplicity. The method converts each instantaneous ECG sample into a phasor, thus being able to deal very precisely with P and T waves, which are of notably lower amplitude than the QRS complex. Initially, the method relies on the detection of R peaks and, next, onset and offset of the QRS complex are identified. Finally, taking the QRS as a reference, P and T waves are detected and delineated. The new delineator has been validated with the QT database, providing average values of sensitivity higher than 98.60% for the detection of all the significant ECG waves and fiducial points. Additionally, the average maximum time delineation error was lower than 6 ms and its standard deviation was in agreement with the accepted tolerances for expert physicians in the onset and offset identification for QRS, P and T waves. As a consequence, this new algorithm is able to achieve similar performance to the one provided by other well known delineation algorithms, but with notably lower computational cost.