1. Department of Thoracic and Cardiovascular Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
2. Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
3. Department of Thoracic and Cardiovascular Surgery, Andong Hospital, Andong, Korea.
4. Department of Emergency Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.