Abstract 19142: Simultaneous Biatrial Epicardial and Endocardial Dominant Frequency and Complex Fractionated Atrial Electrogram Analysis in Chronic Atrial Fibrillation
Introduction: Current methods being developed in catheter ablation of atrial fibrillation (AF) include targeting sites with high dominant frequencies (DF) and complex fractionated atrial electrograms (CFAE). Our knowledge, however, of what DF and CFAE analysis represents and the implications for the underlying atrial substrate is still limited. The specific role of the epicardium in this analysis is not well understood. This study compares DF and CFAE analysis simultaneously between endocardial and epicardial sites in the left and right atrium to determine gradients between these structures.
Methods: Atrial rapid bursting pacemakers were implanted in 4 mongrel dogs to induce and maintain AF for 6 months prior to atrial mapping. Frequency and CFAE analysis were performed simultaneously in the endocardium and epicardium. Endocardial and epicardial sites were matched in location using fluoroscopy and three dimensional mapping. Differences were analyzed with two sided t-testing and reported as mean ± SD.
Results: In the left atrium, mean endocardial DF was greater than mean epicardial DF (9.76 ± 1.63 vs. 8.71 ± 1.92, p=0.0003) with a frequency gradient of 0.511. Electrical activity was also more fractionated in the endocardium as compared to the epicardium (CFAE: 113.1 ± 26.37 vs. 120.7 ± 25.35, p=0.003). In the right atrium, mean epicardial DF was higher than the mean endocardial DF (9.27 ± 1.62 vs. 8.61 ± 1.49, p=0.0016) with a frequency gradient of 0.67. Electrical activity also had a trend toward increased fractionation in the epicardium vs. endocardium (CFAE: 123.0 ± 38.32 vs. 129.4 ± 32.5, p = 0.069).
Conclusions: Maximal fractionated activity appears to be endocardial in the left atria and trends toward the epicardium in the right atria in this chronic AF model. Frequency analysis also supports this with a frequency gradient from the endocardium to the epicardium in the left atria and a reverse gradient from the epicardium to the endocardium in the right atrium. This raises important questions regarding the pathways of signal propagation during AF and ultimately where the necessary sites for successful ablation may lie.
- © 2010 by American Heart Association, Inc.