['Although radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) is an effective rhythm control strategy, there is a substantial amount of recurrence. We explored the predictors of AF recurrence after RFCA with consistent ablation strategy.', 'This study included 575 patients (77% male, 56 ± 11 years old) with AF (65.7% paroxysmal AF [PAF], 34.3% persistent AF [PeAF]) who underwent RFCA. We evaluated the clinical, serological, and electrophysiological parameters thereof.', '1. During 15 ± 7 months of follow-up, patients who experienced AF recurrence (21.8%) were older (58 ± 10 vs. 55 ± 11 years old, p=0.019) and more likely to have PeAF (50.4% vs. 29.4%, p<0.001) and greater LA volume (137.3 ± 49.1 vs. 116.6 ± 37.9 mL, p<0.001). 2. In patients with clinical recurrence after RFCA, both ablation time (110.1 ± 43.8 vs. 92.3 ± 30.1 min, p<0.001) and procedure time (222.7 ± 79.6 vs. 205.8 ± 58.8 min, p<0.001) were prolonged, and the early recurrence rate within 3 months of the procedure was higher (63.0% vs. 26.4%, p<0.001) than those without clinical recurrence. 3. In logistic regression analysis, LA volume (OR 1.008, CI 1.001-1.014), ablation time (per quartile, OR 1.380, CI 1.031-1.847), and early recurrence (OR 3.858, CI 2.420-6.150) were independent risk factors for recurrence of AF after RFCA.'] Is long duration of radiofrequency energy delivery an independent predictor of clinical recurrence after catheter ablation of atrial fibrillation : over 500 cases experience?