There has no evidence for the anticoagulation in patients who had undergone catheter ablation of atrial fibrillation, and has maintained sinus rhythm for more than 1 year. However, anticoagulation can increase the risk of bleeding, the study evaluating the role of oral anticoagulation is needed in this patients. This study will compare the efficacy and safety of non-vitamin K anticoagulants (apixaban) and no oral anticoagulation in patient with sinus rhythm one year after catheter ablation of AF.