Background: Atrial fibrillation (AF) is related to the structural and functional remodeling of the left atrium (LA) and ventricle (LV). Radiofrequency catheter ablation (RFCA) induces reverse remodeling of atrium. However, its mechanism is not clear. Recently, few studies showed that the patients with diastolic dysfunction had a worse outcome of RFCA for AF. The ratio of the early diastolic transmitral flow velocity (E) to the early diastolic mitral annular velocity (E'), E/E', is a reliable diastolic parameter in patients with AF. The objective of this study was to investigate the anatomical & functional changes in patients who underwent RFCA for AF by pre-RFCA & post-RFCA 1 year follow-up echocardiography. Methods: We included 156 patients with AF (male 78.2%, 56.3짹10.7 years old, paroxysmal AF 66.7%) who underwent RFCA, and compared pre-procedural echocardiography and post-RFCA 1-year follow-up echocardiography. Results: 1. LA anterior-posterior diameter (pre 42.1짹5.8mm vs. post 39.1짹5.5mm, p<0.001), early transmitral flow velocity (E; pre 0.71짹0.18m/sec vs. post 0.67짹0.16m/sec, p=0.005), and mitral annular velocity (E���; 7.9짹2.3cm/sec vs. post 7.2짹2.2cm/sec, p<0.001) were decreased 1 year after AF ablation. 2. When we compared the patients with reduced LA size(n=114) and those without LA reverse remodeling(n=42), pre-procedural E/E��� was significantly higher (10.4짹4.0 vs. 8.5짹2.6, p=0.001) in spite of similar left ventricular ejection fraction (p=0.248), and the early recurrence rate within 3months of ablation was lower (27.0% vs. 45.2%, p=0.031) in patients with LA reverse remodeling. 3. However, duration of RF energy delivery (p=0.881) or late recurrence rate (p=0.135) were not different between 2 groups. Conclusion: Pre-procedural diastolic dysfunction, but not the duration of RF energy delivery, was closely related with reverse remodeling of LA after AF catheter ablation, and those without reverse remodeling of LA more frequently suffered from early recurrence of AF after ablation.