Two types of reentry in atrial fibrillation

The isochronal activation maps demonstrate two types of reentry in atrial fibrillation. Map A shows random reentry with three simultaneous wavefronts (black arrows) activating most of the recording area. Map B also shows three simultaneous wavefronts, but they are coming from different directions than those in map A. Maps C and D show two consecutive cycles of complete reentry. The wave of activation (black arrow) spreads clockwise in a circular fashion around a line of unexcited tissue.