Differentiation between epicardial and endocardial conduction gaps for left atrial posterior wall isolation using peak frequency annotation algorithm

A multicenter randomized clinical trial has found that the addition of left atrial posterior wall (LAPW) isolation to pulmonary vein isolation (PVI) did not significantly improve freedom from atrial arrhythmias compared with using PVI alone in patients with persistent atrial fibrillation (AF).1,2 However, LAPW isolation added to PVI is a therapeutic option that could be considered based on individual characteristics in patients with persistent AF. When performing LAPW isolation, a transmural conduction block by left atrial (LA) roof and floor linear ablations remains challenging, mainly due to epicardial muscular fibers that bridge epicardial by endocardial conduction, such as the septopulmonary bundle.