Left atrial volume measured by Cardiac CT as an independent predictor of atrial fibrillation recurrence following catheter ablation

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and is associated with increased risk of stroke, heart failure, and dementia. Catheter ablation is an established treatment, particularly effective in patients with symptomatic paroxysmal AF. However, recurrence rates remain high (30–50%) and are influenced by factors including AF type, left atrial (LA) volume, comorbidities, and procedural expertise. This study aimed to evaluate the association between LA volume measured by cardiac computed tomography (CT) and AF recurrence. Methods: We conducted a retrospective observational study including patients who underwent AF ablation and prior cardiac CT for pulmonary vein mapping between 2018 and 2021 at a high-complexity center in Buenos Aires, Argentina. Patients with prior ablation, follow-up < 12 months, or missing CT were excluded. LA volume was measured automatically excluding the appendage and pulmonary veins, and indexed to body surface area. Recurrence beyond the 3-month blanking period was assessed. Patients were categorized into tertiles based on LA volume. Kaplan-Meier survival and Cox regression analyses were performed. Results: A total of 145 patients were included (mean age 60.2 ± 11.3 years; 24.8% women; 53.7% with hypertension). AF was paroxysmal in 66.2%. Mean LA volume was significantly higher in the recurrence group (142.8 ± 42.5 mL vs. 112.7 ± 29.2 mL; p < 0.001). Recurrence occurred in 26.5%, 46%, and 71.7% across increasing volume tertiles. LA volume in the upper tertile was independently associated with recurrence (HR 1.83; 95% CI 1.05–3.2; p = 0.03). Conclusions: CT-derived LA volume was independently associated with AF recurrence following catheter ablation.