Key Role of Left Atrial Appendage during Redo Ablation in a Case of Long-Standing Persistent Atrial Fibrillation

Figure 1. Activation mapping of the LA and RA. The LAA and surrounding area is in AF (pink, average cycle length 150 ms); the rest of the atria including the anterior and lateral walls of the LA, the interatrial septum, and the RA are in atrial flutter (cycle length 330 ms, earliest in CS 9, 10). Red circle marked the area ablated during CFAE ablation.

Figure 2. Termination of the atrial flutter. Activation mapping showed the mechanism of the atrial flutter to be focal (atrial activation spanning 145 ms, less than one-half of the cycle length of the atrial flutter, which was 330 ms); the earliest point of activation is on the left side of the interatrial septum. A linear area of double potentials with a gap in the middle can be seen from the base of the LAA to the right PV antrum (green dots). The gap is the area of the earliest activation. Radiofrequency energy delivery at the gap (35 W, 3 seconds) terminated the atrial flutter. A paced signal can also be seen from the temporary pacemaker inserted for protection during the procedure. Red circle marked the area ablated during CFAE ablation.

Figure 3. Activation mapping and intracardiac electrograms showing the LAA and surrounding area in AF (pink on activation map, lasso in the LAA) while the rest of the atria (green on the activation map) was in sinus rhythm.

Figure 4. Intracardiac electrograms showing slow spontaneous potentials within the LAA after LAA electrical isolation (lasso in the LAA, no cardioversion done).