1. Division of Cardiovascular Medicine, Department of Internal Medicine, Dankook University Hospital, Dankook University College of Medicine, Cheonan, Korea.
2. Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
4. Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Canada.
5. Statistics and Data Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
7. Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
8. Department of Internal Medicine and Heart Center, Chonnam National University Hospital, Gwangju, Korea.