1. Division of Cardiology, Yonsei University Health System, Seoul, Korea.
2. Department of Cardiology, Seoul National University Hospital, Seoul, Korea.
3. Division of Cardiology, Keimyung University Hospital, Daegu, Korea.
4. Department of Cardiology, Ewha Womans University Hospital, Seoul, Korea.
5. Division of Cardiology, Daegu Catholic University Hospital, Daegu, Korea.
6. Division of Cardiology, Eulji University Hospital, Daejeon, Korea.
7. Department of Cardiology, Korea University Hospital, Seoul, Korea.
8. Department of Cardiology, CHA Bundang University Hospital, Seongnam, Korea.
9. Department of Cardiology, Seoul National University Bundang Hospital, Seongnam, Korea.