1. Division of Cardiology, Daegu Catholic University College of Medicine, Daegu, Korea.
2. Division of Cardiology, Daegu Fatima General Hospital, Daegu, Korea.
3. Division of Cardiology, Yeungnam University College of Medicine, Daegu, Korea.
4. Division of Cardiology, Kyungpook National University, Daegu, Korea.
5. Division of Cardiology, Keimyung University Dongsan Medical Center, Daegu, Korea.
6. Division of Cardiology, Daegu Veterans Hospital, Daegu, Korea.
7. Division of Cardiology, Kyungpook National University Chilgok Hospital, Daegu, Korea.