Cardioembolic stroke is approximately 30% of brain infarction, and most of the embolus sources are atrial fibrillation (AF). Brain infarction with AF was associated with an elderly woman, main brain arterial occlusion, and large infarcts. Therefore, patient outcome is so sever, and mortality is very high compared with other stroke types. Use of the anticoagulant before stroke onset is only 32%, and less than 1.6 of PT-INR was 58.4%. The hospitalized recurrence was 7.5%, which was not higher than stroke patients without AF. For detection of the intracardiac tthrombus, transesophageal cardiac-echogram detected thrombus in 16.4%. Within five years after discharge, mortality rate was higher in stroke patients with AF than those without AF. Brain infarction with AF should be knock-out stroke.