AIMS: We sought to investigate the time course of cardiac disorders after catheter ablation for atrial fibrillation (AF) in patients with coexisting heart failure (HF) during long-term follow-up. METHODS AND RESULTS: We analysed consecutive 280 patients undergoing first-time catheter ablation for AF who had coexisting HF, which was defined as prior HF hospitalization, estimated right ventricular systolic pressure ≥45 mmHg, or B-type natriuretic peptide (BNP) ≥200 pg/dL before the procedure. The primary endpoints were improvements in left ventricular ejection fraction (LVEF), E/e', BNP, left atrial dimension (LAD), and mitral regurgitation (MR) at 1 year. The secondary endpoints were serial changes of LVEF, E/e', BNP, LAD, and MR at 6 months, 1 year, and 5 years and cumulative incidence of HF hospitalization. During the mean follow-up of 5.1 ± 3.0 years, 70.7% of patients were free from recurrent AF. Among patients with LVEF < 50%, E/e' ≥ 15, BNP ≥ 200 pg/dL, LAD ≥ 40 mm, and moderate-to-severe MR, changes in those parameters from baseline to 1 year were 34.5 ± 9.9% to 43.2 ± 14.4% (P < 0.001), 19.7 ± 3.9 to 12.5 ± 6.6 (P < 0.001), 290 to 85 pg/dL (P < 0.001), and 100% to 37.8% (P < 0.001), respectively. The improvements in the cardiac disorders were maintained up to 5 years except for E/e'. In patients with LVEF < 40%, significant delayed improvement of LVEF beyond 1 year was observed (ΔLVEF = 10.5 ± 18.5, P = 0.001), but not in patients with LVEF of 40-49%. The cumulative incidence of HF hospitalization was 12.6% at 5 years. Baseline diastolic dysfunction was the only independent predictor for subsequent HF hospitalization. CONCLUSIONS: In patients undergoing AF ablation with coexisting HF, all cardiac disorders significantly improved after the procedure, which was mostly maintained during 5 year follow-up.