Background Pulmonary veins (PV) and the atria undergo electrical and structural remodeling in atrial fibrillation (AF). This study aimed to determine PV and left atrial (LA) reverse remodeling after catheter ablation for AF assessed by chest computed tomography (CT). Methods PV electrophysiologic studies and catheter ablation were performed in 63 patients (68% male; mean +/- SD age: 56 +/- 10 years) with symptomatic AF (49% paroxysmal, 51% persistent). Chest CT was performed before and 3 months after catheter ablation. Results At baseline, patients with persistent AF had a greater LA volume (91 +/- 29 cm(3) vs. 66 +/- 27 cm(3); P = 0.003) and mean PV ostial area (241 +/- 43 mm(2) vs. 212 +/- 47 mm(2); P = 0.03) than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients (76%) were AF free on or off antiarrhythmic drugs. There was a significant reduction in LA volume (77 +/- 31 cm(3) to 70 +/- 28 cm(3); P < 0.001) and mean PV ostial area (224 +/- 48 mm(2) to 182 +/- 43 mm(2); P < 0.001). Patients with persistent AF had more reduction in LA volume (11.8 +/- 12.8 cm(3) vs. 4.0 +/- 11.2 cm(3); P = 0.04) and PV ostial area (62 mm(2) vs. 34 mm(2); P = 0.04) than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume (r = 0.38, P = 0.03). Conclusions Catheter ablation of AF improves structural remodeling of PV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.