Association and Predictive Value of Left Atrial Epicardial Adipose Tissue and HFpEF in Atrial Fibrillation

Abstract 2303084, presented at Western Atrial Fibrillation Symposium 2026

Atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) share a bidirectional relationship strongly influenced by obesity. Epicardial adipose tissue (EAT), a visceral fat depot with key endo-paracrine effects, may contribute to this relationship. We aimed to evaluate the association between left atrial EAT (LA-EAT) and HFpEF and to determine whether it adds predictive value to the H₂FPEF scoreBaseline characteristics and medical history were obtained from Cardiac Arrhythmia Data Repository (CADRe), an IRB approved registry at the University of Washington. LA-EAT volume was quantified from cardiac MRI scans acquired with Dixon Sequences.We included 204 patients (mean age 66.1 ± 11.2 years; 66.5% male; BMI 28.6 ± 6.4 kg/m²; LVEF 61.2 ± 6.3%). Paroxysmal AF was present in 141 patients (69.4%), and HFpEF in 57 (27.9%). LA-EAT volume was significantly higher in patients with HFpEF compared with those without (38.37 mL vs. 26.47 mL; p < 0.001). LA-EAT also increased significantly with H₂FPEF score categories (F(6,196) = 3.64, p = 0.001) (Panel C). LA-EAT was stratified into tertiles: Compared with the lowest tertile, the second and third LA EAT tertiles were associated with significantly increased odds of HFpEF (OR = 3.81; 95% CI 1.47–11.19; and OR = 8.56; 95% CI 3.48–24.46; respectively; both p < 0.001). The H₂FPEF score itself was associated with HFpEF diagnosis (OR = 2.46; 95% CI 1.88–3.32; p < 0.001) and demonstrated good discriminative ability (AUROC = 0.80; p < 0.001). Incorporating LA-EAT tertile points (0 for the first tertile, 1 for the second, and 2 for the third) modestly increased model discrimination (AUROC = 0.83; p < 0.001). However, DeLong’s test showed no statistically significant difference between the original H₂FPEF model and the LA-EAT augmented model (p = 0.23).In AF patients, Left atrial epicardial adipose tissue volume was strongly associated with HFpEF and increased with higher H₂FPEF scores but offered no predictive capacity beyond H₂FPEF score. Longitudinal studies are needed to further characterize this relationship and incorporate explore total EAT's role.