1. Division of Cardiology, Department of Internal Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.
2. Division of Cardiology, Department of Internal Medicine, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Department of Internal Medicine, CHA Bundang Medical Center, CHA University College of Medicine, Seongnam, Korea.