Abstract 4652: Incidence and Mode of AF Termination During Substrate Ablation of AF Guided Solely by Complex Fractionated Atrial Electrograms Mapping

Abstract

One of the key end points of catheter ablation of atrial fibrillation (AF) substrate guided by complex fractionated atrial electrograms (CFAE) mapping is termination of sustained AF. But controversy exists as to how effective CAFÉ ablation is in AF termination especially in chronic AF. Thus, we carried out the following study to determine incidence and mode of AF termination including electrogram characteristics at the successful site. Methods: Our study included 616 consecutive patients (pts); 206 (33%) were paroxysmal (PAF) and 410 (67%) chronic (CAF), who underwent CFAE ablation from Jan 2006 to Dec 2007. The recordings of electrograms at baseline, during AF termination and cycle length changes were analyzed blindly off-line; the sites of successful termination were then associated with the detailed grid of 44 regions of both atria and coronary sinus (CS). Results: Of the 616 Pts, AF could be terminated in 203 (99 %) of PAF (64 pts [31%] with Ibutilide [Ib] ), 80% in CAF (283 pts [69%] with Ib); the remaining 20% of the chronic AF Pts required cardioversion. The termination sites were located 76% in LA, 11% in CS, and 13% in RA. The common areas of the termination are at the upper septum at the anterior aspect of the right pulmonary veins (PVs), proximal CS, posterior aspects of the left PV antrums, the ridge of LA appendage, and postero-septum of RA. AF organized and changed to atrial flutter (Afl) in 121 pts (35%), while 342 pts (65%) of the patients remained in AF with a significant increase (164 to 247 msec) in cycle length before termination. There are 3 distinct electrogram characteristics at the successful sites of tachycardia termination; 1) low voltage CFAE which the shortest cycle length in relation to the rest of the atria (42%); 2) mid-diastolic and fractionated potentials in patients whose AF converted to Afl (45%) and 3) a very low voltage fractionated potentials with the highest amplitude of the potentials was ≤ 0.06 mV (0.044 ± 0.011 mV), commonly found at the previous ablation sites (13%). Conclusion: Substrate ablation guided by CFAE mapping successfully terminate AF in the majority of Pts. Knowledge of specific areas that have predilection to be sites of termination and electrogram characteristics may be helpful to achieve AF termination.