Abstract 2348: Mechanisms Responsible for the Termination of Atrial Fibrillation Assessed by Non-contact Mapping System
Background: Previous studies have shown the mechanisms responsible for the initiation and the maintenance of atrial fibrillation (AF) in a variety of animal and human models. However, little is known regarding the termination mechanisms of human AF. This study is aimed to assess the termination mechanisms of AF by evaluating the relationship between AF termination and the left atrial anatomical structures.
Methods: We studied 106 patients (86 men, mean age; 61±12 years) with paroxysmal AF (n=80) and persistent AF (n=26). They underwent mapping of the left atrium (LA) and the pulmonary vein (PV) using non-contact mapping system (NCMS). Activation sequences on isopotential color maps at the time of the spontaneous termination of AF were analyzed.
Results: We recorded 19 AF terminations in 17 patients. Six terminations were abandoned from the analysis because of the existence of the QRS complex. In 10 (77%) of the residual 13 terminations, the significant prolongation of AF cycle length by 42±29 ms measured in the distal coronary sinus (CS) and organized CS activation sequence was observed just 2.0±1.6 seconds before the AF termination. Among the 9 terminations recorded after PV isolation (PVI), 6 terminations showed that activation wave fronts disappeared after they encountered the ablation line of PVI and the other 3 terminations showed that they were moving near the LA roof and disappeared after they were standing still there for a while. Among the 4 terminations recorded before PVI, 2 terminations showed that two activation wave fronts collided with each other at the anterior or posterior wall of LA and disappeared. Another termination showed that activation wave front disappeared after it encountered the ridge between left PVs and LA appendage (LAA), and the other termination showed that it was moving up the posterior wall of LA and disappeared around the LA roof.
Conclusions: These findings suggest that the ablation line of PVI and the specific anatomical structures such as LA roof or the ridge between left PVs and LAA may be associated with the spontaneous wave breakup and may play an important role in termination of AF.