[1] Osaka City Univ, Grad Sch Med Internal Med & Cardiol, Osaka 558, Japan
[2] Yokosuka Kyosai Gen Hosp, Yokosuka, Kanagawa, Japan
[3] Univ Tsukuba, Div Cardiovasc, Tsukuba, Ibaraki 305, Japan
[4] Natl Cardiovasc Ctr, Suita, Osaka, Japan
[5] Minist Hlth Labour & Welf, Labour Insurance Appeal Comm, Tokyo, Japan