1. Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea.
2. Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine and Cardiovascular Center,
Yongin Severance Hospital, Yongin, Korea.
3. Division of Cardiology, Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
4. Division of Cardiovascular Medicine, Department of Internal Medicine, Dankook University Hospital, Dankook University School of Medicine, Cheonan, Korea.