1. Department of Applied Statistics, Gachon University, Seongnam, Korea.
2. Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
3. Department of Cardiology, Daejeon St. Mary's Hospital, The Catholic University of Korea, Daejeon, Korea.
4. Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.