1. Division of Cardiology, Department of Internal Medicine, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Division of Cardiology, Hallym University Sacred Heart Hospital, Anyang, Korea.
3. Department of Cardiology, Busan Paik Hospital, Inje University College of Medicine , Busan, Korea.
4. Division of Cardiology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Korea.
5. Division of Cardiology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University College of Medicine, Seoul, Korea.
6. Department of Cardiology, Dong-A University Hospital, Busan, Korea.