Increasing Left Atrial Epicardial Adiposity with Regional Heterogeneity in Vagal Type Atrial Fibrillation

Introduction: Epicardial adipose tissue (EAT) contains ganglionated plexi (GP) that can cause initiation of atrial fibrillation (AF).The purpose of this study was to investigate the amount and distributional difference of LA adiposity between the patients with sympathetic and vagal AF. Methods: The study included 16 consecutive patients (53±12 y/o, male 14) with frequent attacks of sympatomatic paroxysmal AF. All cases underwent 24hour ambulatory Holter monitoring before Catheter ablation. Onset of AF accompanied with increased HF component and decreased L/H ratio was designated as vagal AF (Group 1, n=8); whereas decreased HF component and increased L/H ratio was classified as sympathetic AF (Group 2, n=8). EAT was evaluated by using MDCT and acquired semi-automatically tracing the axial images from pulmonary artery to coronary sinus. The regional distribution of EAT was assessed by dividing the left atrial (LA) surface into 8 equal regions. Results: The total EAT volume was higher in Group 1, compared to that of Group 2 (30.1±7.2 vs. 22.0±6.2 cm3, p=0.03). There was a significant increase of EAT volume in the left anterior wall in Group 1, when compared to that of Group 2 (9.9±3.5 vs. 6.2±2.4 cm3, p=0.04). Conclusions: Increasing EAT with regional heterogeneity appears to be associated with vagal AF, suggesting the EAT involves in the autonomic remodeling process.