[1] Tohoku Univ, Grad Sch Med, Dept Cardiovasc Med, Sendai, Miyagi 980, Japan
[2] Tohoku Univ, Grad Schs Biomed Engn, Sendai, Miyagi 980, Japan
[3] Natl Cerbral & Cardiovasc Cntr, Dept Cardiovasc Med, Osaka, Japan
[4] Tohoku Univ, Grad Schs Engn, Sendai, Miyagi 980, Japan