Prognostic Implications of Right and Left Atrial Enlargement after Radiofrequency Catheter Ablation in Patients with Nonvalvular Atrial Fibrillation

Background and Objectives: The prognostic role of the right atrium (RA) compared with that of the left atrium (LA) is unclear in patients with atrial fibrillation (AF). We assessed structural changes in both atria and determined their association with recurrence of AF after radiofrequency catheter ablation (RFCA). Subjects and Methods: All 111 patients with nonvalvular AF (87 men; mean age, $57{\pm}11$ years; 68 with paroxysmal AF) who underwent RFCA were enrolled consecutively. Three-dimensional volumes of both atria measured from computed tomography images were compared between subjects with and without recurrence of AF during the follow-up. Results: Early (<3 months), 6-month, and 1-year recurrence was documented in 26 (24%), 30 (27%), and 36 (32%) patients, respectively. Significantly larger RA and LA volume indices (RAVI and LAVI) were observed in the early, 6-month, and 1-year recurrence groups (p<<.05 for all). In multivariate analysis, Early recurrence was independently associated with RAVI (for each 10 mL/m2 increase; odds ratio [OR], 1.31; 95% confidence interval [CI], 1.03-1.66, p= 0.03), but not with LAVI. However, both RAVI and LAVI failed to predict 6-month outcomes independently. LAVI was the only independent predictor of 1-year recurrence (for each 10 mL/m2 increase; OR, 1.36; 95% CI, 1.08-1.71, p=0.009). Conclusion: RA enlargement was more closely related to early recurrence of AF after RFCA than LA size. However, LA size, rather than RA volume, was a determinant of long-term AF prognosis after RFCA. These findings suggest a temporal pattern in the prognostic implication of enlargement in each atrium that switches over time after RFCA for AF.