[1] Keio Univ, Sch Med, Dept Cardiol, Tokyo, Japan
[2] Univ Tokyo, Dept Healthcare Qual Assessment, Tokyo, Japan
[3] Saiseikai Utsunomiya Hosp, Dept Cardiol, Utsunomiya, Tochigi, Japan
[4] Natl Hosp Org, Saitama Natl Hosp, Dept Cardiol, Saitama, Japan
[5] Yokohama Municipal Citizens Hosp, Dept Cardiol, Yokohama, Kanagawa, Japan
[6] Saiseikai Cent Hosp, Dept Cardiol, Tokyo, Japan
[7] St Lukes Int Hosp, Cardiovasc Ctr, Dept Cardiol, Tokyo, Japan
[8] Natl Canc Ctr, Ctr Canc Control & Informat Serv, Div Hlth Serv Res, Tokyo 104, Japan