Early Versus Late Initiation of Anticoagulation in Mild-to-moderate AIS Patients With NVAF

Inclusion Criteria: * Age \> 18 years old * Acute ischemic stroke with onset \< 48 hours * Have a history or newly diagnosed as NVAF * NIHSS on admission \<= 8 Exclusion Criteria: * Chronic renal dysfunction (GFR \< 30ml/min) or severe hepatic injury * Have a history or newly diagnosed as valvular heart disease * Mural thrombus in heart * Contraindications of anticoagulation therapy within 12 days after AIS, e.g. severe intracranial hemorrhage * Received reperfusion therapy, e.g. intravenous thrombolysis and endovascular treatment * Concomitant stenosis (\>50%) of carotid artery/intracranial artery, of which the ischemic lesion located within the territory * Life expectancy less than 1 year * Plan to receive invasive surgery in the following 3 months and have high risk of uncontrollable bleeding * Pregnant or lactating women * Individuals identified by researchers as unsuitable for participation in the study due to other reasons.