Abstract
Introduction: Focal activation is believed to be an atrial
fibrillation (AF) driver; however, little is known about whether all
focal activations are necessary for AF persistence. The purpose of this
study was to assess the electrical nature of focal activation and
identify high-priority focal activations using a novel mapping system
(CARTOFINDER).
Methods: Thirty-five patients with persistent AF who underwent
catheter ablation were assessed. Cycle length (CL) and CL standard
deviation (CLSD) on unipolar recordings and voltage amplitude and
electrogram morphologies on bipolar recordings were evaluated at all
points of interest. The most frequent CL at each mapping site was
defined as the dominant CL. We identified dominant focal activations
(DFAs) that had a shorter dominant CL on the integrated CARTOFINDER map.
The effect of elimination of DFAs on AF maintenance was assessed by the
composite endpoint (termination to sinus rhythm, organization of the
rhythm to atrial tachycardia, and AF CL slowing).
Results: In all, 450 focal activations were identified among
10,868 points, and 50.4% of focal activations were DFAs. Focal
activations showed relatively long CL and regularity with short CLSD.
Most focal activations showed an isoelectric baseline and were located
outside of the fractionated electrogram area. Both DFAs and non-DFAs
were typically observed in normal voltage range. Elimination of DFAs was
achieved in 19 (54.3%) patients, with a remarkable impact on AF
maintenance (68.4% vs. 25.0%, p = 0.018).
Conclusions: DFAs may play an important role in AF maintenance
and could be an attractive therapeutic target for AF.
Keywords: atrial fibrillation, driver, focal activation,
CARTOFINDER, dominant cycle length.