1. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2. Division of Cardiology, Department of Internal Medicine, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Korea.
3. Division of Cardiology, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
4. Department of Cardiovascular Medicine, Chonnam National University Hospital, Gwangju, Korea.
5. Division of Cardiology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Division of Cardiology, Department of Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
7. Division of Cardiology, Department of Medicine, Yonsei University College of Medicine, Seoul, Korea.
8. Department of Internal Medicine, Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.