1. Division of Cardiology, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea
2. Cardiovascular Center, Chonnam National University Hospital, Chonnam National University
3. Division of Cardiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea
4. Division of Cardiology, Seoul St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea