Abstract 1838: Mechanisms of the Maintenance of Atrial Fibrillation: Role of the Complex Fractionated Atrial Electrograms Region Assessed by Non-contact Mapping
Background: Complex fractionated atrial electrograms (CFAE) have been implicated as the substrate of atrial fibrillation (AF). However, its role for the maintenance of AF has not been well clarified.
Objectives: The purpose of this study was to investigate the mechanisms of the perpetuation of AF, especially in relation to the CFAE region.
Methods: In 9 patients with paroxysmal AF, endocardial mapping of the left atrium was performed during AF using 3D non-contact mapping system (EnSite 3000). The location of the CFAE region was identified by the non-contact Laplacian bipolar recordings validated with contact bipolar electrograms. The activation sequence of the wave, the wave break-up and wave fusion, and the location of the focal firing driver were analyzed during AF. If the initiators or drivers were derived from the pulmonary vein (PV), the arrhythmogenic PVs were isolated or encircled. Those from non-PV foci were ablated focally and then linear roof line ablation was performed.
Results: The CFAE were located at the roof (89%), anterior (78%), posterior (67%), PV (67%), appendage (56%) and septum (33%), respectively. The area of the CFAE was 12.4±6.1 cm2. During AF, 1 to 4 (mean: 2.7±1.0) meandering waves were observed. Each wave propagated over various pathways and no stable constant reentrant circuit was found. The CFAE region provided conduction delay and produced wave break-up (5.7±3.5 times/second), resulted in the generation of a new wave. No wave break-up was found in the non-CFAE region. The wave fusion at the CFAE region was more frequently observed than that at the non-CFAE region (7.9±6.8 vs. 2.4±3.0 times/second, p<0.02). The waves which were fused at the CFAE region organized into a new wave, then propagated to the next adjacent excitable region. The focal firing drivers were found at the PV and the sites within the CFAE region and there was no significant difference between them (2.0±2.1 vs. 1.6±2.0 times/second, p=NS). After ablation, AF was terminated in 5 patients (56%).
Conclusions: The CFAE region plays an important role for the perpetuation of AF. In addition to the focal firing from the PV and the CFAE region, wave fusion and wave break-up at the CFAE region sustained wave propagation, resulted in the maintenance of the AF.