[1] Tohoku Univ, Sch Med, Dept Internal Med 1, Sendai, Miyagi 9808574, Japan
[2] Sendai City Med Ctr, Div Cardiol, Sendai, Miyagi 9830824, Japan
[3] Iwate Cent Prefectural Hosp, Div Cardiol, Morioka, Iwate 0200066, Japan
[4] Tohoku Kosai Hosp, Div Cardiol, Sendai, Miyagi 9808674, Japan
[5] Sendai Cardiovasc Ctr, Sendai, Miyagi 9813107, Japan