1. Division of Cardiology, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
2. Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
4. Division of Cardiology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.
5. Division of Cardiology, Hallym University Medical Center, Pyungchon, Korea.