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

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).

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.

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.

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