Catheter ablation of premature ventricular complexes (PVC) improves left ventricular (LV) systolic performance in certain patients; however, the effect on diastolic function and left atrial (LA) remodeling is unclear. We assessed the effects of catheter ablation of PVCs on parameters of LV diastolic function and LA remodeling. Forty-seven patients (age 65 +/- 10 years, 46 men) who underwent catheter ablation for symptomatic PVCs were evaluated using two-dimensional echocardiography before and 6 +/- 2 months after ablation. The measured diastolic indices included mitral inflow parameters (E wave, A wave, E/A ratio, and deceleration time (DT)), mitral lateral annulus early diastolic velocity (Ea), and E/Ea ratio. The LA volume was measured using modified biplane Simpson's method. We also compared the changes in the left atrial volumes and left atrial volume index (LAVI) after PVC ablation. After catheter ablation of PVCs, the mean LV ejection fraction (EF) increased significantly (49.9 +/- 10.3 vs. 42.8 +/- 11.8, p < 0.01). Significant improvement was also seen in A wave velocity (71.3 +/- 17.1 vs. 59.5 +/- 15.1 cm/s, p = 0.039), E/A ratio (1.42 +/- 0.6 vs. 1.07 +/- 0.5 ml, p = 0.034), Ea (8.9 +/- 3.9 vs. 6.8 +/- 2.9 cm/s, p = 0.04), and E/Ea ratio (15.4 +/- 5.8 vs. 10.6 +/- 3.4, p = 0.027), whereas mitral E and DT did not show significant change. LAVI decreased significantly after ablation (44.4 +/- 14.8 vs. 36.7 +/- 12.5, p < 0.001). Significant improvement in LAVI was also seen in patients with normal baseline LVEF (p = 0.04). Catheter ablation of PVCs improved LV diastolic function and resulted in left atrial reverse remodeling.