Atrial volumetrics and recurrence after catheter ablation for atrial fibrillation.

Background: While left atrial (LA) volume enlargement is a well-known predictor of recurrence after catheter ablation for atrial fibrillation (AF), the association between the recurrence and other atrial volumetrics remains uncertain. This study aimed to assess the association between various atrial volumetrics and the 12-month recurrence of AF after catheter ablation (AFCA). Methods: Patients with a history of AFCA who underwent pre-procedural cardiac computed tomography were retrospectively included. Atrial volumes were measured using artificial intelligence-based segmentation software (AutoSeg-H). Atrial volumetrics included total LA, LA body, LA appendage (LAA), total right atrium (RA), RA body, and RA appendage (RAA) volumes. AF recurrence was defined as any documented atrial arrhythmia (AA) within 12 months following AFCA. All volumetrics were dichotomized using cutoffs that optimally predicted 12-month AA recurrence on the receiver operating characteristic curve. Cox regression models were used to estimate adjusted hazard ratios (aHRs) of the dichotomized volumetrics. Results: Among 199 included patients, 45 (22.6%) underwent AA recurrence within 12 months. All atrial volumetrics were significantly higher in the recurrence group than in the non-recurrence group. Optimal cutoffs used for dichotomizing volumetrics were: total LA ≥129.1, LA body ≥112.0, LAA ≥15.3, total RA ≥123.0, RA body ≥82.1, and RAA ≥13.2 (unit: mL). All dichotomized volumetrics, except RAA ≥ 13.2, were significantly associated with recurrence. LAA volume ≥15.3 [aHR 1.97; 95% confidence interval (CI), 1.04-3.74; Conclusions: Most dichotomized atrial volumetrics were associated with 12-month AA recurrence after AFCA. In particular, LAA ≥15.3 mL and RA body ≥82.1 mL were independently associated with recurrence, suggesting that structural remodeling in these regions may contribute to post-ablation AA recurrence.