Background: Results of Complex Fractionated Atrial Electrograms (CFAE) ablation in atrial fibrillation (AF) are conflicting, partially due to the subjectivity of visual analysis. CFAE algorithms provided by 3D mapping systems lack selectivity. We sought to demonstrate the improved selectivity of a new CFAE CARTO® Shortest Complex Interval (SCI) algorithm setting compared to the traditional nominal setting.

Methods: 32 patients (60.4 ± 12.7 years) with paroxysmal (n=3), persistent (n=16) or permanent (n=13) AF (duration=56 ± 65 months) underwent visual CFAE ablation, while CFAE maps of left atrium (LA) were drawn. Maps were further reanalyzed with two different settings: nominal (SCI 60-120 ms 0.05-0.15mV) vs. customized setting (SCI 30-40ms 0,04-0.15mV). Automatically detected areas of CFAE (CARTO-CFAE) were measured and compared with the visually targeted areas (ablation point = 60 mm2) to assess their accuracy to define CFAE areas of clinical significance.

Results: AF was terminated by ablation in 30 patients (93.7%). With the new CARTO SCI setting, both CARTO-CFAE areas and ablated proportions outside CFAE areas were reduced (30.6±20.5 cm² vs. 68.8±24.5 cm², p < 0.0001, and 1.86±1.82 % vs. 3±3%, p =0.003), while ablation surface inside CARTO-CFAE areas was larger than with the nominal setting (38.2±19.6% vs. 20.4±17.5 %^, p = 0.008).

Conclusion: This new CFAE algorithm setting is significantly more selective than the nominal one, and focuses on visually ablated areas leading to a high AF termination rate.