1. Department of Cardiology, Chungnam National University Hospital, Chungnam National University, Daejeon, Korea.
2. Department of Cardiology, Chonbuk National University Hospital, Chonbuk National University, Jeonju, Korea.
3. Department of Cardiothoracic Surgery, Chungnam National University Hospital, Chungnam National University, Daejeon, Korea.
4. Department of Cardiothoracic Surgery, Chonbuk National University Hospital, Chonbuk National University, Jeonju, Korea.