Epicardial adipose tissue (EAT) around the left atrium (LA) can change the electric conduction of the LA, potentially leading to atrial fibrillation (AF).

The aim of this study was to evaluate whether an association existed between EAT and the electrophysiological properties of adjacent atrial myocardium in patients with AF.

A total of 201 consecutive patients referred for initial AF catheter ablation were prospectively included. A preprocedural computed tomography scan was performed to assess total and LA-EAT parameters. Detailed point-by-point voltage mapping using an electroanatomical mapping system was realised to assess the LA low-voltage zone (LVZ), defined as an area with bipolar electrograms ≤0.5 mV during sinus rhythm.

Ninety-one (91) patients (45.3%) presented at least one LVZ. They had a significantly more severe AF pattern (p=0.04) than patients without LVZ, and little difference existed with regard to other clinical variables. Patients with LVZ presented significantly more total EAT volume (162.4±71.3 mL vs 135.5±57.2 mL; p=0.03) and LA-EAT volume (26.4±15.9 mL vs 20.9±10.5 mL; p<0.01) than no-LVZ patients. Multivariable logistic regression analyses revealed total EAT volume index to be an independent predictor of the presence of LVZ (odds ratio [OR] 1.01; 95% confidence interval [CI] 1.01–1.04; p<0.01) and LA-EAT percentage to be an independent predictor of severe LVZ (OR 1.34; 95% CI 1.18–1.64; p<0.001).

The EAT volume and its distribution around the LA may indicate the presence and severity of LVZ. The assessment of the volume of EAT and its distribution may lead to better risk stratification in patients with AF.