1. Division of Cardiology, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong, Korea.
2. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
3. Department of Cardiology, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea.
4. Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea.
5. Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, Korea.
6. Department of Internal Medicine, College of Medicine, Gyeongsang National University and Hospital, Jinju, Korea.
7. Department of Cardiovascular Medicine, Kyung Hee University Hospital, Seoul, Korea.