[1] Chiba Hokusoh Hosp, Nippon Med Sch, Div Intens Care Unit, 1715 Kamagari, Inzai, Chiba 2701694, Japan
[2] Toho Kamagaya Hosp, Dept Internal Med, Chiba, Japan
[3] Hasegawa Hosp, Dept Internal Med, Chiba, Japan
[4] Kanamachi Daiichi Hosp, Dept Internal Med, Tokyo, Japan
[5] Nippon Med Coll Hosp, Dept Cardiovasc Med, Tokyo, Japan