1. Cardiology Division, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
2. Cardiology Division, Department of Internal Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Cardiology Division, Department of Internal Medicine, Chungju Medical Center, Chungju, Korea.
4. Cardiology Division, Department of Internal Medicine, NHIC Ilsan Hospital, Goyang, Korea.
5. Department of Biochemistry, CHA University College of Medicine, Seongnam, Korea.