1. Cardiovascular Center, Hanyang University Guri Hospital, Guri, Korea.
2. Division of Cardiology, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea.
3. Division of Cardiology, Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
4. Division of Cardiology, Department of Internal Medicine, Chonnam National University Hospital, Gwangju, Korea.
5. Division of Cardiology, Department of Internal Medicine, Gachon Medical School Gil Medical Center, Incheon, Korea.
6. Department of Internal Medicine, Nowon Eulji Medical Center, Eulji University College of Medicine, Seoul, Korea.
7. Division of Cardiology, Department of Internal Medicine, Hanllym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea.