1. Division of Cardiology, Division of Cardiology, Hyosung hospital, Cheong-Ju, Republic of Korea
2. Division of Cardiology, Daejeon St. Mary’s hospital, College of Medicine, The Catholic University of Korea
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