P2756Atrial remodeling features in CT to predict the recurrence of atrial fibrillation after ablation therapy

Objective: Atrial fibrillation (AF) is the most common arrhythmia and is associated with significant morbidity and mortality. Structural atrial remodeling triggers increased automaticity and is important for AF recurrence and persistence. We evaluated qualitative atrial and ventricular CT-features to predict AF recurrence after ablation therapy. Methods: Five-hundred forty-two consecutive patients with non-valvular, drug-resistant AF (15.5% persistent) and without significant comorbidities underwent cardiac CT angiography before AF ablation. CT images were evaluated for left and right atrial (RA) diameters and volume, left atrial (LA) wall thickness (LAWT, anterior and posterior), left and right ventricular epicardial adipose tissue diameter (EAT) and epicardial fat density in the interventricular sulcus. Close clinical follow-up was performed for at least 12 months. Interrater variability was assessed. Results: Of 542 patients (mean age 56y, 24% female), 262 (48.3%) had a recurrence of AF after a mean of 7 months (mean follow-up period 31 months). CT analysis showed significantly larger LA (46.6±15.7 ml/m2 vs. 41.8±13.7 ml/m2, p<0.0001) and RA indexed volumes (36.5±12.6 ml/m2 vs. 31.9±10.0 ml/m2, p<0.0001) in patients with recurrent AF. Furthermore, mean LAWT measurements were significantly higher in patients with AF recurrences, in anterior (1.92±0.6 mm vs. 1.52±0.5 mm, p<0.0001), posterior (1.46±0.4 mm vs. 1.28±0.5 mm, p=0.0001), right lateral (1.75±0.6 vs. 1.49±0.5 p<0.0001) and left portion of the LA (1.79±0.5 vs. 1.47±0.5, p<0.0001). Epicardial adipose tissue showed significant lower amount between the patient cohorts at the RV basis (4.1±1.6mm vs 4.4±1.9mm, p=0.032) and LV basis (1.9±1.1mm vs. 2.2±1.3mm, p=0.009) but not mid-ventricular or apically. Lipid density values were significantly lower (-107.7±16.6 HU vs. -112.7±16.3 HU, p=0.001) in patients with AF recurrences.