Fig. 5

Epicardial high-resolution mapping of the atria. Atrial electrograms recorded during sinus rhythm (SR), atrial pacing (P) and (electrically induced) atrial fibrillation (AF) obtained during the epicardial mapping procedure are shown in the upper panel. The left lower panel shows an example of an activation map during electrically induced AF of the right atrium in a patient undergoing coronary artery bypass grafting without a history of AF. Isochrones are drawn at 5 ms, areas of conduction block are indicated by black bars, the origin of peripheral and epicardial breakthrough waves by respectively grey dots and white asterisks. The arrows indicate main activation direction. Corresponding wavemap is displayed in the right lower panel. The wavemap shows the different types of fibrillation waves entering the mapping area from various directions. These maps are used to determine the incidence of e.g. conduction block and epicardial breakthrough