Identification of regions maintaining atrial fibrillation through cycle length and cycle length gradient mapping

Background: Visualizing the specific regions where atrial fibrillation (AF) is maintained is crucial for effective treatment, but it remains challenging in clinical practice. We aimed to address this challenge by developing a mapping approach focused on the cycle length (CL) and its gradient (CL-gradient).

Methods: In 105 patients undergoing initial ablation for persistent AF, pre-ablation CARTOFINDER data were utilized to create maps based on three indicators: (1) CL, the atrial frequency during AF calculated using CARTOFINDER; (2) Short CL, encompassing CLs within 5 ms of the minimum CL; and (3) CL-gradient, the CL range within a 6 mm radius. We evaluated the association between the AF termination through ablation and the measured values and patterns in each map.

Results: AF termination occurred in 17 patients. The AF termination group exhibited the significant large maximum CL-gradient (48.8 ms [interquartile range, 38.6-66.3], p <.001) and the short distance between the minimum CL site and the maximum CL-gradient site (15.8 mm, [interquartile range, 6.0-23.2], p =.029). Of the 17 AF termination cases, 13 exhibited a CL distribution pattern characterized by a steep CL-gradient near the minimum CL site (SG-MCL), defined as the distance of less than 23.2 mm and the maximum CL-gradient greater than 33.1 ms. In these AF termination cases, SG-MCL was also correlated with the ablation area.

Conclusions: The minimum CL area accompanied by significant CL gradients in the immediate vicinity may play a crucial role in sustaining AF.