[1] Sungkyunkwan Univ, Sch Med, Dept Med, Cardiac & Vasc Ctr,Samsung Med Ctr, Seoul 135710, South Korea
[2] Sungkyunkwan Univ, Sch Med, Dept Pediat, Cardiac & Vasc Ctr,Samsung Med Ctr, Seoul 135710, South Korea
[3] Chungnam Natl Univ, Sch Med, Dept Internal Med, Taejon, South Korea