Complex fractionated electrograms and AF nests in vagally mediated atrial fibrillation.

BACKGROUND

Catheter ablation targeting of complex fractionated atrial electrograms (CFAEs) is one of the techniques used for atrial fibrillation (AF) ablation. The ablation of sites showing a high-frequency spectral component (HFC) during sinus rhythm, known as AF nests, has been introduced as an adjunct to conventional ablation. Known locations of some AF nests are similar to CFAE sites. However, it has not been systematically evaluated whether these two targets represent the same foci. The purpose of this study was to compare the anatomical locations of these sites using an animal model of vagally mediated AF.

METHODS

Five anesthetized open-chest dogs were evaluated. Atrial electrograms were obtained epicardially. AF was induced by burst atrial pacing with 20 Hz during vagal stimulation. A total of 15 sites (eight sites in right atrium and seven sites in left atrium) were evaluated in each animal. The CFAE was determined during AF according to the electrogram patterns. After sinus conversion, real-time spectrum analysis was used for AF nest assessment at the same location.

RESULTS

The CFAE was observed at the high and mid sulcus terminalis areas, pulmonary vein antrum, and mid portion of the coronary sinus. Among them, only 60% of the CFAE sites showed HFC during sinus rhythm. In addition, some of the non-CFAE sites (22%) showed HFC during sinus rhythm.

CONCLUSION

The CFAE sites were not the same as the AF nests in this animal model of vagally mediated AF. Therefore, these two types of ablation methods appear to target different substrates of AF.