Clinical Research Directory

Inclusion Criteria: * Age\>=80 years * Has been diagnosed atrial fibrillation * Has history of ischemic stroke or transient ischemic attack * Has any of the bleeding risk lists below * bodyweight \< 60 kg * creatinine clearance \< 50 mL/min * history of major bleeding or gastrointestinal bleeding * concurrent use of antiplatelet agents (such as aspirin, clopidogrel, ticagrelor, prasugrel, cilostazol), non-steroidal anti-inflammatory drugs, amiodarone, tacrolimus, cyclosporine, dronedarone. Exclusion Criteria: * Has ever used anticoagulants, defined as: * warfarin therapy within 1 month before study enrollment. * using heparin, low molecular weight heparin or direct oral anticoagulants within 7 days before study enrollment. * allergy to edoxaban * under regular dialysis, includes hemodialysis or peritoneal dialysis * refuse to provide informed consent.