AB-452663-3 DISTRIBUTION OF TRIGGERS IN THE LEFT ATRIAL POSTERIOR WALL IN AF PATIENTS UNDERGOING CATHETER ABLATION

Abstract

Having a common embryologic origin with the pulmonary veins (PVs), left atrial posterior wall (LAPW) is considered to be a source of non-PV triggers that facilitate maintenance of atrial fibrillation (AF). However, the benefits of electrical isolation of the posterior wall (PWI) is still debated with contradictory data originating from different ablation approaches. . We report the distribution of triggers in the LAPW area in AF patients undergoing repeat ablation. Consecutive AF patients undergoing catheter ablation between 2015 and 2022 were included in this analysis. PVs were isolated first. Next, high-dose isoproterenol challenge (up to 30μg/min) was used to disclose triggers in the PW by moving the circular mapping catheter along the PW down to the level of coronary sinus, which were targeted using additional RF energy. We defined lower part of LAPW as the area between the line joining the inferior borders of the inferior PV-encircling lesions and the coronary sinus. The endpoint was to achieve electrical isolation, as documented by absence of any electrical activity in the PW. Of the 10,390 AF ablations performed during the specified time period, 5843 (56.2%) had triggers mapped and ablated in the LAPW area. Triggers were seen to be originating from the part of the PW between the PVs in 3809 (65.2%), from the lower part of the PW in 2028 (34.7%) and focal triggers from all over the PW including the lower part in 1519 (26%) cases. All triggers were targeted for ablation. Figure 1 demonstrates the triggers arising from lower PW. Ectopic triggers in the LAPW were documented to be arising from the lower part of the PW in a large number of cases. Thus, operators should consider extending the ablation to include the lower LAPW area to maximize the benefits of PWI.