A. Recent ischemic stroke (including transient ischemic attack with positive neuroimaging) visualized by brain imaging that is not lacunar B. Abscence of ≥ 50% stenosis or occlusion in cervical and intracranial arteries supplying ischemic area C. No atrial fibrillation after ≥ 24-hour Holter monitoring D. No intra-cardiac thrombus on transthoracic echocardiography E. No other major cardioembolic sources F. No other specific cause of stroke (for example, arteritis, dissection, migraine/vasospasm, drug abuse)