Associations Between Atrial Epicardial Fat Quantified by Semi-Automated CT Segmentation and Gender, BMI, Cholesterol Levels in AF Patients: Results from the Prospective AFAT Study

Abstract Background Epicardial adipose tissue (EAT) is defined as adipose tissue (epicardial fat) between the myocardium and the visceral pericardium. Recent evidence suggests that EAT may play important roles in regard to atrial fibrillation (AF) burden as well as other cardiovascular diseases through complex inflammatory mechanisms. Current evidence regarding the relationship of atrial EAT and BMI, gender or cardiovascular risk factors is mixed. Methods and Results We conducted a prospective observational study (AFAT) at the German Heart centre in Munich with 200 patients aimed to be included. This represents an interim analysis of the first 75 patients enrolled in the AFAT study. All patients received delayed dual source cardiac computer tomography (CT) imaging which was analysed using 3D segmentation (Figure 1) to quantify left atrial (LA) and right atrial (RA) EAT prior to receiving catheter ablation for AF. The mean age was 67 ± 8.7 years with 46.9 % being female (n=35) and the mean BMI was 28 ± 4.5. Mean LA EAT was 33.1 ml ± 13.2 ml and RA EAT was 32.7 ml ± 12.2ml with a total mean atrial EAT volume of 65.4 ml ± 10.2 ml. Volumes of the left- and right atrial EAT were significantly correlated in our sample (p < 0.001; Pearson correlation coefficient r=0.9). The mean total EAT Volume was significantly larger in males than in females (74 ml vs. 52 ml, p < 0.001) (Figure 2). Linear regression analysis adjusted for cofounders demonstrated significantly larger mean atrial EAT volumes in patients with higher body mass index (p = 0.001) and with increased age (p=0.006). Increased HbA1c levels or increased total cholesterol levels were not associated with higher total atrial EAT Levels (respectively, p=0.066 and p=0.22). Conclusion Semi-automated CT based atrial segmentation is a novel highly accurate and reproducible way to reliably identify atrial EAT. Left and right atrial EAT volumes are significantly intercorrelated. In this study BMI, Age and male gender were independently associated with higher EAT levels.Visualization of atrial EATGender differences in atrial EAT (ml)