Click on image to view larger version.

Figure 3 Surface electrocardiographic, left atrial appendage (LAA) pacing stimulus artifact (PSA) and right atrial (RA) and left atrial (LA) recordings after complete interatrial conduction block. In the left half of the figure, there is no pacing. The left atrium is electrically quiescent. In the right half of the figure, LAA pacing (arrow) demonstrates left atrial capture (arrowhead), which is dissociated from the right atrium.