Atrial Fibrillation ECG Signal Processing for QRST Cancellation: Zero-Padding Versus Time Alignment

In non-invasive analysis of atrial fibrillation (AF), the QRST cancellation is commonly applied by using a time-aligned average over several ECG cycles. This paper proposes another technique with less illusive high frequency content into the residual signal. Firstly the QRS complexes and T-end were detected by Pan-Tompkins's technique and Zhang's algorithm respectively. Subsequently, the QRST segment was determined in each period of the ECG signal. Then, two different approaches (time-aligned and zero padding) were applied to remove the QRST segments from each period and make the signal ready for AF analysis. To compare the effectiveness of the QRST cancellation approaches, mean spectral power of the residual signal at high frequency bands (upper 12 Hz) was used. The results indicated a superiority of the time-aligned averaging method for the application of AF analysis.