1. Division of Cardiology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Pediatrics Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Division of Cardiology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
4. Division of Cardiology, Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.