1. Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Division of Cardiology, Myongji Hospital, Goyang, Korea.
3. Department of Surgery, Sungkyunkwan University School of Medicine, Seoul, Korea.
4. Departement of Surgery, Yonsei University College of Medicine, Seoul, Korea.
5. Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea.