This study aims to compare the efficacy and safety of the edoxaban and the warfarin in atrial fibrillation patients with mitral stenosis. The study design is a multicenter, randomized, open-label, investigator initiated phase 2 trial. The patients were randomly assigned to Edoxaban or Warfarin groups. Primary outcome was a composite of stroke and systemic arterial thromboembolism. The safety outcome was major bleeding.