1. Division of Cardiology, Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.
2. Division of Cardiology, Department of Internal Medicine, Kosin University Gospel Hospital, Busan, Korea.
3. East Lancashire Hospitals NHS Trust, Blackburn, Lancashire, UK.
4. Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.