1. Division of Cardiology, Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.
2. Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
3. Division of Cardiology, Department of Internal Medicine, University of Ulsan College of Medicine, Gangneung Asan Hospital, Gangneung, Korea.
4. East Lancashire Hospitals NHS Trust, Blackburn, Lancashire, UK.
5. Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.