Fig. 2.

Schematic representation of the phase analysis process for detection of the wavefront activation. Fibrillatory unipolar signals are recorded and pre-processed by a 50 Hz alternate current filter, low-pass filter designed with a 100 Hz cut-off, and a baseline wander removal based on the wavelets. The complex wave is canceled by a template subtraction algorithm. First, a distinct V wave complex from the spline closest to mitral annulus is identified (first row), with an ambiguous V wave from the furthest spline (second row) coupled. Second, the fibrillatory signals are marked with the negative dV/dt max to directly compute the phase. The signals are then subjected to fast Fourier transform analysis, and finally the frequency spectrum is determined.