Characteristics and distribution of complex fractionated atrial electrograms and the dominant frequency during atrial fibrillation: relationship to the response and outcome of circumferential pulmonary vein isolation.

BACKGROUND: Although sites of complex fractionated electrograms (CFAEs) and dominant frequency (DF) are known to be critical for the maintenance of atrial fibrillation (AF), spatial distribution of CFAEs and DF and their impact on the outcome of AF ablation remain unclear.

METHODS: We created CFAE and DF maps of the left atrium (LA), right atrium, and pulmonary veins (PVs) with a NavX mapping system and simultaneously calculated the DF values with a Bard LabSystem Pro in 40 patients with AF (nonparoxysmal, n = 16).

RESULTS: In 19 patients in whom circumferential PV isolation (CPVI) terminated AF, there was a high DF in the PVs (Bard-based DF value, 6.70 ± 1.01 Hz), low DF in the LA body (5.94 ± 0.75 Hz), and a significant PV-to-LA body DF gradient (0.76 ± 0.65 Hz), and the CFAEs were located mainly in the PV antrum. In the 21 patients not responding to CPVI, a high DF was located in both the PVs (7.04 ± 0.81 Hz) and LA body (6.75 ± 0.81 Hz), and therefore, the PV-to-LA body DF gradient was smaller than that in the CPVI responders (0.29 ± 0.52 Hz, P = 0.0160), and the CFAEs extended to the LA body. The higher DF in the LA body, nonparoxysmal AF, and longer AF duration remained as independent predictors of a post-ablation AF recurrence by using a multivariate analysis.

CONCLUSIONS: A higher LA-DF value, smaller PV-to-LA DF gradient, and wider LA-CFAE distribution were noted more often in the nonresponders to CPVI than in the responders. This suggested the presence of an arrhythmogenic substrate in the LA beyond the PVs in patients whose AF persisted after CPVI, which was further associated with post-ablation AF recurrence.