Introduction: Epicardial adipose tissue (EAT) is associated with atrial fibrillation (AF), possibly because of adverse paracrine signaling to adjacent atrial substrate. However, few studies have explored relations between left atrial EAT (LAEAT), cardiac structure and function, and outcomes in patients with AF.
Methods: We performed a retrospective analysis of 255 consecutive patients with AF referred to the University of Massachusetts Medical Center (UMMC) AF Treatment program for catheter ablation (CA). LAEAT was measured using pre-defined axial slices of pre-ablation CT scans and then indexed to body surface area (BSA). Patients were divided into tertiles (low, intermediate, high) of indexed LAEAT area (iLAEAT). Clinical, echocardiographic data and AF recurrence rates were compared across tertiles of iLAEAT. We performed logistic regression analysis adjusting for factors known to be associated with AF and cardiac remodeling.
Results: 104 (41%) of participants had AF recurrence over 12-months follow up. Higher iLAEAT was associated with greater left atrial diameter and volume (p<0.05). Participants in the highest iLAEAT tertile had higher CHA2DS2VASC scores, were more likely to be male, had persistent AF, and were more likely to have had a prior cardioversion than participants in the lowest iLAEAT tertile (Table 1, p for all <0.05). In regression analyses adjusting for clinical and echocardiographic variables associated with AF, iLAEAT was associated with 3-fold higher odds of AF recurrence (Odds Ratio= 3.1; 95% Confidence Interval 1.6-5.9).
Conclusions: Indexed left atrial epicardial adipose tissue area is a novel marker for estimating burden of left atrial fat that can be easily calculated from CT images. iLAEAT is associated with increased LA volume, type of AF (persistent vs. paroxysmal), and greater likelihood of AF recurrence. Further research is needed to examine the mechanisms underlying the observed association between iLAEAT and AF recurrence.