1. The Heart Center of Chonnam National University Hospital, Gwangju, Korea.
2. The Cardiovascular Center, Hanseo Hospital, Busan, Korea.
3. Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea.
4. Department of Internal Medicine, Yeungnam University Hospital, Daegu, Korea.
5. Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Korea.
6. Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
7. Department of Internal Medicine, Pusan National University Hospital, Busan, Korea.
8. Department of Internal Medicine, Yonsei University Severans Hospital, Seoul, Korea.
9. Department of Internal Medicine, Chungbuk National University Hospital, Cheongju, Korea.
10. Department of Internal Medicine, Kyunghee University College of Medicine, Seoul, Korea.
11. Department of Internal Medicine, The Catholic University of Korea Hospital, Seoul, Korea.
12. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.