Atrial fibrillation modifies the association between CT-derived epicardial adipose tissue volume and left atrial remodeling in valvular heart disease.

BACKGROUND: Epicardial adipose tissue volume (EATv) is associated with atrial fibrillation (AF), but whether AF modifies the association between EATv and atrial remodeling in valvular heart disease remains unclear. OBJECTIVE: To determine whether AF modifies the association between CT-derived EATv and left atrial remodeling. METHODS: This retrospective valvular surgery cohort included 436 patients (218 AF, 218 sinus rhythm [SR]) after 1:1 propensity score matching. Multivariable linear and logistic regression assessed associations of EATv with left atrial volume index (LAVI) and left atrial enlargement (LAE). Restricted cubic spline, ROC curve and mitral regurgitation-stratified sensitivity analyses were performed. Exploratory histology and EAT secretome analyses were conducted in surgical samples. RESULTS: Patients with AF had higher EATv and larger atria than those with SR. In the primary adjusted model, each 10-cm3 increase in EATv was associated with a 1.21-mL/m2 higher LAVI in SR and a 4.45-mL/m2 higher LAVI in AF (P for interaction = .002). EATv was associated with LAE (OR 1.29, 95% CI 1.17-1.43), with a significant AF-by-EATv interaction (OR 1.41, 95% CI 1.15-1.74). Adding EATv improved discrimination for LAE (AUC 0.767 to 0.804; P = .007). Exploratory tissue analyses suggested adipocyte hypertrophy, fibrosis, and reduced Wnt-antagonist secretion in AF-associated EAT. CONCLUSIONS: Higher CT-derived EATv was associated with more advanced left atrial remodeling, with stronger associations in AF than in SR. EATv may serve as a CT-derived marker of remodeling vulnerability in valvular heart disease.