1. Department of Neurology, Sejong General Hospital, 91-121 Sosabon 2-dong, Sosa-gu, Bucheon-si, Gyeonggi-do 422-711, Republic of Korea
2. Department of Thoracic and Cardiovascular Surgery, Sejong General Hospital, Bucheon 422-711, Republic of Korea
3. Department of Cardiology, Sejong General Hospital, Bucheon 422-711, Republic of Korea