Early Administration of Edoxaban After Acute Ischemic Stroke in Patients With Non-valvular Atrial Fibrillation

Inclusion Criteria: 1. Acute ischemic strokes (\< 48 h from symptom onset) showing ischemic lesions confirmed by DWI, which are attributable to atrial fibrillation 2. Evidence of persistent or paroxysmal atrial fibrillation (already known or newly detected) 3. Age ≥20 y 4. Patients who provided informed consent Exclusion Criteria: 1. Transient ischemic attack with no DWI lesions or severe ischemic strokes (NIHSS \>16) 2. Significant hemorrhagic transformation (parenchymal hematoma type I or type II by the ECASS definition or those accompanying with worsening of an existing focal neurological deficit \[NIHSS ≥4\])10 on baseline MRI 3. Mechanical heart valve, rheumatic heart valve disease, or any other conditions requiring strong anticoagulation such as vitamin K antagonist or heparin treatment 4. Concomitant significant atherosclerotic stenosis (\>50%) in the proximal arteries, which are possibly responsible for stroke lesions 5. Recent (\<3 months) history of cerebral bleeding 6. Active internal bleeding or clinically significant bleeding 7. Severe anemia (Hb \<10 g/dL) or bleeding diathesis (platelet count \<100,000/uL or PT-INR \>1.7) (If there is no active bleeding sign, it is permitted to enroll Hb \<9 g/dL , platelet count \<70,000/uL) 8. Uncontrolled hypertension: persistent systolic pressure \>180 mmHg or diastolic pressure \>110 mmHg 9. Active, advanced medical diseases (liver, kidney, pulmonary disease or cancer) with a life expectancy \<6 months 10. Renal impairment (CrCl \<30 mL/min) or undergoing Hemodialysis (or Peritoneal Dialysis) 11. Treatment with a strong inducer of p-glycoprotein (carbamazepine, dexamethasone, doxorubicin, nefazodone, pentobarbital, phenobarbital, prazocin, rifampin, St.John's wort, tenofovir, tipranavir, trazodone, vinblastine) 12. Contraindication to MRI 13. Pregnancy, breast-feeding or having a plan to be pregnant 14. Participation in the other investigational drug trials simultaneously or within 3 months before the first administration of the study medication. Observational studies without an intervention (eg study medication) are allowed. 15. Any clinical conditions (eg abnormal lab tests) unsuitable for undergoing clinical trials at the discretion of the clinical investigators 16. Known hypersensitivity to the study drug (edoxaban), its ingredients, or formulation excipients 17. Patient with liver disease related to coagulation disorder and clinically significant bleeding risk 18. Severe Liver disease 19. Patient who has increase risk of bleeding due to the following disease * recent gastrointestinal ulcer history * carcinoma increased risk of bleeding * recent brain or spinal injury * recent brain, spinal or optical surgery histroy * esophageal varix * arteriovenous malformations * vascular aneurysms (over 3.5cm) * intra spinal or cerebral vascular disorder 20. Patient with other anticoagulants 21. intermitant or severe mitral stenosis 22. a pulmonary embolism patient who is hemodynamic unstabled or required thrombolytic therpy or pulmonary emnolectomy