1. Division of Cardiology, Department of Internal Medicine, Ewha Womans University Medical Center, Ewha Womans University School of Medicine, Seoul, Korea.
2. Division of Cardiology, Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Department of Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
4. Department of Cardiology, Sejong General Hospital, Incheon, Korea.
5. Division of Cardiology, Department of Internal Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Department of Internal Medicine, Cardiovascular Center and Cardiology Division, Eunpyeong St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
7. Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, Seoul, Korea.
8. Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.