1. Division of Cardiology, Department of Internal Medicine, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea.
2. Division of Cardiology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
3. Division of Nephrology, Department of Internal Medicine, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea.