1. Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea.
2. Department of Cardiovascular Medicine, Chonnam National University Hospital and Medical School, Gwangju, Korea.
3. Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
4. Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
5. Cardiovascular Center, Korea University Guro Hospital, Seoul, Korea.
6. Department of Internal Medicine, Gyeongsang National University Hospital, Jinju, Korea.