1. Division of Cardiology, Department of Internal Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Department of Medicine, Inje University Ilsan Paik Hospital, Goyang, Korea.
3. Department of Medicine, Keimyung University Dongsan Medical Center, Daegu, Korea.
4. Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
5. Division of Cardiology, Dietrich Bonhoeffer Hospital, Academic Teaching Hospital of University of Greifswald, Greifswald, Germany.
6. Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.
7. Institute on Aging, Seoul National University, Seoul, Korea.