1. Cardiovascular Center, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
2. Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
3. Department of Internal Medicine, Inje University Ilsan Paik Hospital, Goyang, Korea.
4. Department of Internal Medicine, Sejong General Hospital, Bucheon, Korea.
5. Department of Internal Medicine and Cardiovascular Center, Presbyterian Medical Center, Jeonju, Korea.
6. Cardiovascular Center, Korea University Guro Hospital, Seoul, Korea.
7. Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
8. Department of Internal Medicine, Inha University Hospital, Incheon, Korea.
9. Department of Internal Medicine, Pusan National University Hospital, Busan, Korea.
10. Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea.
11. Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
12. Department of Internal Medicine, Chungnam National University College of Medicine, Daejeon, Korea.
13. Department of Internal Medicine, Chungbuk National University College of Medicine, Cheongju, Korea.