Epicardial fat (EF) plays an established role in genesis and persistence of atrial fibrillation (AF) but its impact on endocavitary radiofrequency (RF) ablation remains not considered. This study sought to determine the impact of EF volume on duration of RF during AF ablation procedure.

EF volume was assessed by computed tomography scans that were systematically performed before ablation. Primary endpoints were total duration of RF and duration of pulmonary vein isolation. Secondary endpoint was the conversion or organization of an arrhythmia after pulmonary vein isolation. The mean follow-up duration was 18±7.3 month.

A total of 165 subjects, including 72 persistent AF patients, benefit from a first endocavitary RF ablation procedure from March 2015 to July 2017 in Reims university hospital. Persistent AF patients had higher total EF volume than paroxysmal AF patients (72.5±31.7 vs. 55.8±24.5ml; P=0.0002). Total duration of RF and duration of pulmonary vein isolation were significantly associated with higher total EF volume (respectively P=0.007 and P=0.037) and peri-ventricular EF volume (P=0.009 and P=0.029). In multivariate analysis, total EF volume was not significantly associated with total duration of RF (P=0.46). Regarding individuals with arrhythmia at the time of the procedure, patients whose AF was reduced or organized after pulmonary vein isolation had no less total EF than those whose AF was not (62.6±36.7 vs. 71.3±31.5ml; P=0.112) (Fig. 1).

We highlight a significative association between total, especially peri-ventricular EF volume, and total duration of RF and duration of pulmonary vein isolation. This relation was no more significant in multivariate analysis which gives EF the state of marker of ablation complexity. These results support the causal link between epicardial fat and AF and emphasize the importance of peri-ventricular EF role.