1. Cardiovascular Center, Korea University Guro Hospital, Seoul, Korea.
2. Research Institute of Health Sciences, Korea University College of Health Science, Seoul, Korea.
3. Department of Thoracic and Cardiovascular Surgery, Korea University Guro Hospital, Seoul, Korea.
4. Department of Medicine, The Second Affiliated Hospital of Kunming Medical University, Kunming, China.
5. Department of Medicine, Korea University Graduate School, Seoul, Korea.