Stroke characteristics and laboratory investigations. Data on stroke characteristics will be collected at admission, including symptoms at time of onset and pre-hospital delay. Severity of stroke will be measured on the National Institutes of Health Stroke Scale (NIHSS) by physicians certified by the Clinical Research Center for Stroke in Korea. The course of the disease during admission will be established, including treatments and complications. On discharge, each case of ischemic stroke will be classified according to the TOAST classification. Modified Rankin Scale (mRS) and Barthel index scores will also be obtained at discharge. Laboratory investigations including complete blood cell count, erythrocyte sedimentation rate, C-reactive protein, urinalysis, urine pregnancy test, serum electrolytes, liver function test, renal function tests, chest X-ray and electrocardiogram will be checked in the emergency department. Other specific laboratory investigations such as fasting blood glucose, hemoglobin A1C, lipid panel test, thyroid function test, rheumatologic panel tests, hypercoagulable panel tests, heavy metal tests, homocysteine and α-galactosidase will be checked on the day after admission, following overnight fasting. For the genetic test for CADASIL, investigators will ask for a further informed consent. All patients will undergo cardiac evaluation during the admission period, including 24-hour Holter monitoring, transthoracic echocardiography and transesophageal echocardiography.