[1] Korea Univ, Anam Hosp, Div Cardiol, Dept Internal Med,Coll Med, 73 Goryeodae Ro, Seoul 02841, South Korea
[2] Hanyang Univ, Div Cardiol, Dept Internal Med, Coll Med, Seoul, South Korea
[3] Korea Univ, Dept Internal Med, Grad Sch, Seoul, South Korea
[4] Korea Univ, Anam Hosp, Dept Thorac & Cardiovasc Surg, Coll Med, Seoul, South Korea
[5] Sungkyunkwan Univ, Sch Med, Heart Vasc Stroke Inst, Dept Med,Div Cardiol,Samsung Med Ctr, Seoul, South Korea
[6] Yonsei Univ, Coll Med, Severance Cardiovasc Hosp, Div Cardiol, Seoul, South Korea
[7] Ewha Womans Univ, Dept Cardiol, Seoul Hosp, Sch Med, Seoul, South Korea
[8] Konkuk Univ, Div Cardiol, Dept Med, Med Ctr, Seoul, South Korea
[9] Chungbuk Natl Univ, Dept Internal Med, Coll Med, Cheongju, South Korea
[10] Inje Univ, Ilsan Paik Hosp, Div Cardiol, Dept Internal Med,Coll Med, Goyang, South Korea
[11] Chung Ang Univ Hosp, Div Cardiol, Dept Med, Seoul, South Korea
[12] Chungnam Natl Univ Hosp, Div Cardiol, Dept Internal Med, Daejeon, South Korea
[13] Inha Univ Hosp, Div Cardiol, Dept Med, Incheon, South Korea
[14] Dankook Univ, Dankook Univ Hosp, Div Cardiovasc Med, Dept Internal Med,Coll Med, Cheonan, South Korea
[15] Korea Univ, Dept Biostat, Coll Med, Seoul, South Korea