Elderly people more than 70 years develop atrial fibrillation that causes stroke 
and heart failure. Furthermore, the elderly people who have atrial fibrillation 
accompany many risk factor, and develop cerebral infarction easily. Therefore, 
it is very important to prevent cerebral infarction using anticoagulant drugs. 
So far we usually use warfarin, which has many limitations, especially cerebral 
bleeding. Now new anticoagulant drugs(dabigatran and rivaroxaban) can become 
available. Therefore, we have to learn how to use those drugs. They have to 
carefully be used because they discharge from kidney and old aged patients have 
potential renal dysfunction. We mainly explain anticoagulant therapy in old aged 
patients.