1 Division of Cardiology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Banpodaero 222, Seocho-gu, Seoul 06591, Republic of Korea.
2 Division of Cardiology, Department of Internal Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Uijeongbu, Republic of Korea.
3 Department of Thoracic and Cardiovascular Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea.