Figure 1.

Typical reentrant excitation patterns during atrial fibrillation (AF) visualized by noninvasive phase mapping. Unclosed phase front (the border between red and purple colors) is seen. The phase singularities, marked by white and black points are located at the front ends. The phase front is rotating around phase singularities forming a pair of rotors with opposite chiralities, rotating clockwise and counterclockwise. At the same time, the phase singularities (rotor cores) meander along the atrial surfaces (near the left atrial appendage [LAA] and at the lateral wall of the right atrium [RA])