Epicardial fat is associated with prevalent heart failure and adverse cardiac remodeling in atrial fibrillation

Atrial fibrillation (AF) frequently coexists with cardiometabolic conditions such as diabetes and heart failure (HF), which increase morbidity and mortality. While body mass index (BMI) is widely used for risk stratification, regional adiposity measures including epicardial adipose tissue (EAT) and EAT indexed to body surface area (iEAT) may better reflect local cardiac fat burden and its association with conditions of adverse cardiac remodeling. We identified 348 participants from an AF registry with EAT area quantified from a pre-ablation CT scan. Echocardiographic parameters and clinical covariates were collected from the electronic medical record. Adiposity measures were analyzed in tertiles. Multivariable logistic regression models adjusted for age, sex, and race assessed associations between adiposity and outcomes. ROC curves were used to compare predictive performance. Multivariable linear regression analysis assessed echocardiographic parameters, including left ventricular (LV) ejection fraction, LV dimensions, LV mass, left atrial anteroposterior diameter, and pulmonary artery systolic pressure. Among 348 participants, higher BMI, EAT and iEAT were each associated with older age and increased prevalence of cardiometabolic comorbidity. In multivariable models, the highest tertiles of EAT and iEAT were each independently associated with heart failure EAT OR 4.83 (95% CI 1.82–12.84); iEAT OR 4.40 (95% CI 1.70–11.43). ROC analysis showed that iEAT best discriminated heart failure (AUC = 0.74), while BMI best discriminated diabetes (AUC = 0.69). In adjusted models, all three adiposity metrics were significantly associated with higher LV mass; EAT and iEAT were additionally linked to higher pulmonary artery systolic pressure. In patients with atrial fibrillation, epicardial adiposity measures were more strongly associated with prevalent heart failure than BMI, possibly due to its association with adverse cardiac remodeling. In contrast, BMI remains a stronger predictor of diabetes. Incorporating epicardial fat may enhance risk stratification for heart failure in patients with atrial fibrillation beyond BMI alone.