1. Division of Cardiology, Department of Internal Medicine, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Hallym University Sacred Heart Hospital, Anyang, Korea.
4. Division of Cardiology, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
5. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.