[1] Seoul Natl Univ, Dept Internal Med, Bundang Hosp, Seoul 151, South Korea
[2] Seoul Natl Univ Hosp, Dept Internal Med, Seoul, South Korea
[3] Seoul Natl Univ Hosp, Ctr Cardiovasc, Seoul, South Korea
[4] Seoul Natl Univ, Mol Med & Biopharm Sci, Seoul, South Korea
[5] Samsung Med Ctr, Heart Vasc Stroke Inst, Dept Internal Med, Div Cardiol, Seoul, South Korea