1. Division of Cardiology, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea.
2. Division of Cardiology, Department of Internal Medicine, National Medical Center, Seoul, Korea.
3. Division of Cardiology, Department of Internal Medicine, Ewha Womans University Medical Center, Ewha Womans University School of Medicine, Seoul, Korea.
4. Division of Cardiology, Department of Internal Medicine, Hanyang University Guri Hospital, Guri, Korea.
5. Division of Cardiology, Department of Internal Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
6. Division of Cardiology, Department of Internal Medicine, Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
7. Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea.
8. Division of Cardiology, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Seoul, Korea.
9. Division of Cardiology, Department of Internal Medicine, Soonchunhyang Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
10. Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Korea.
11. Division of Cardiology, Department of Internal Medicine, Hallym University College of Medicine, Seoul, Korea.