Department of Thoracic Cardiovascular Surgery, Yonsei University College of Medicine, Korea.
Address for correspondence: Hyo Chae Paik, M.D. Department of Thoracic Cardiovascular Surgery, Yonsei University College of Medicine, Yongdong Severance Hospital, Kangnamku Dogokdong 146-92, Seoul, 135-720, Korea. Phone: 02-3497-3380, Fax: 02-3461-8282, hcpaik@yumc.yonsei.ac.kr