Substrate modification by adding ablation of localized complex fractionated electrograms after stepwise linear ablation in persistent atrial fibrillation

Linear left atrial (LA) ablation in patients with persistent atrial fibrillation (PsAF) resulting in the elimination of most complex fractionated electrogram (CFE) sites has been demonstrated. This study was designed to evaluate the impact of a localized CFE ablation in addition to a representative linear LA ablation in patients with PsAF. A total of 40 consecutive patients with PsAF underwent construction of CFE and dominant frequency (DF) maps using NavX. A stepwise linear ablation including at the PV antra, septum, roof, mitral annulus, and ridge of the appendage was performed followed by additional ablation of localized CFEs detected by an automatic algorithm. A significant reduction in the continuous CFE burden (< 50 ms) after the linear ablation (69 vs. 21 %; P < 0.0001) was confirmed, and localized CFEs (40-120 ms) were observed with a significant predilection for the anterior (30 %), posterior (30 %), and inferior LA (38 %) regions (P < 0.01). Comparing the localized CFEs with higher frequency sources, 45 % (70/156) of the localized CFE sites included continuous CFE regions, and 59 % (92/156) of those sites overlapped with the high-DF sites (> 8 Hz). Additional localized CFE-targeted ablation further terminated PsAF in 20 % of the patients and further increased the mean CFE cycle length (110 +/- 31 to 125 +/- 39 ms; P = 0.0033) and decreased the DF (6.0 +/- 0.8 to 5.7 +/- 0.7 Hz; P = 0.0013) within the CS. The presence of localized CFE sites with a predilection for particular LA regions after a representative linear LA ablation could provide the optimal sites for selective substrate modification of the atrial fibrillation substrate in patients with PsAF.