1. Department of Internal Medicine, Division of Cardiology, Seoul St. Mary's Hospital, College of Medicine The Catholic University of Korea Seoul Korea
2. Cardiovascular Research Institute for Intractable Disease, College of Medicine The Catholic University of Korea Seoul Korea
3. Department of Internal Medicine, Division of Cardiology, St. Vincent's Hospital, College of Medicine The Catholic University of Korea Suwon Korea
4. Department of Internal Medicine, Division of Cardiology, Eunpyeong St. Mary's Hospital, College of Medicine The Catholic University of Korea Seoul Korea