1. Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
2. Cardiovascular Center, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
3. Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Pusan National University of Medicine, Yangsan, Korea.
4. Division of Cardiology, Department of Internal Medicine, Soonchunhyang University Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
5. Division of Cardiology, Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
6. Division of Cardiology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
7. Division of Cardiology, Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea.