Toru Ikegawa
Keio University
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Basic Research in Cardiology | 1991
Makoto Akaishi; Toru Ikegawa; Yasuhiro Nishikawa; Hitoshi Yokozuka; Shunnosuke Handa; Yoshiro Nakamura
SummaryHypokinetic myocardial segment motion is observed in various pathophysiologic conditions. The aim of this study was to clarify the mechanisms involved in differences in segment motion of hypokinesis. Nineteen open-chest dogs were studied with regard to myocardial segment length, left ventricular pressure, and internal minor-axis diameter. Sequential instantaneous myocardial elastance [α(t) curve] was calculated under 4 different hypoxic conditions: complete coronary occlusion and reperfusion, partial coronary occlusion, coronary microembolization, and anoxic perfusion. The α(t) curve peaked at end-systole in the case of normal contraction; but it was almost totally flat when complete bulging occurred. The hypokinesis which occurred during development of the complete systolic bulgc immediately after complete coronary occlusion had an earlier α(t) peak curve than the hypokinesis resulting from partial coronary stenosis (209.5 ± 35.6 ms after end-diastole vs. 261.9 ± 18.2 ms; p < 0.02), microsphere injection into the coronary artery (243.2 ± 24.5 ms vs. 289.3 ± 15.4 ms; p < 0.05), or anoxic perfusion (213.4 ± 40.2 vs. 275.6 ± 28.3 ms; p < 0.05). The early a(t) peak resulted in a late-systolic bulge in segment length motion. In conclusion, hypokinetic segment motion differed depending on whether the coronary blood flow was present or not. A late-systolic bulge only developed immediately after complete coronary occlusion, and resulted from an abrupt decrease in myocardial stiffness during the cardiac cycle, which is closely related to the abrupt cessation of coronary blood flow.
Japanese Circulation Journal-english Edition | 1988
Satoshi Ogawa; Takashi Sakai; Michiyo Hosokawa; Toru Ikegawa; Hitoshi Yokozuka; Toshihisa Miyazaki; Kenji Sakurai; Yoshiro Nakamura
Japanese Heart Journal | 1986
Toru Ikegawa; Masao Chino; Fumihiko Usuba; Kuni Nishikawa; Yoshiro Nakamura
Japanese Heart Journal | 1993
Tsutomu Yoshikawa; Makoto Akaishi; Fumihiko Ikeda; Toru Ikegawa; Shunnosuke Handa; Yoshiro Nakamura
Japanese Circulation Journal-english Edition | 1989
Toru Ikegawa; Makoto Akaishi; Yasuhiro Nishikawa; Hitoshi Yokozuka; Shinya Goto; Takashi Matubara; Shunnosuke Handa; Yoshiro Nakamura
Japanese Circulation Journal-english Edition | 1989
Shinya Goto; Makoto Akaishi; Toru Ikegawa; Yasuhiro Nishikawa; Hitoshi Yokozuka; Takashi Matsubara; Shunnosuke Handa; Yoshiro Nakamura
Japanese Circulation Journal-english Edition | 1989
Tsutomu Yoshikawa; Makoto Akaishi; Fumihiko Ikeda; Toru Ikegawa; Koji Negishi; Shunnosuke Handa; Yoshiro Nakamura
Japanese Circulation Journal-english Edition | 1988
Yumiko Wainai; Shunnosuke Handa; Shiro Iwanaga; S Kyotani; T Sato; Masatoshi Kusuhara; Fumihiko Ikeda; Yasuhiro Nishikawa; Toru Ikegawa
Japanese Circulation Journal-english Edition | 1987
Toru Ikegawa; Makoto Akaishi; Yasuhiko Nishikawa; Hitoshi Yokozuka; Shunnosuke Handa; Yoshiro Nakamura
Japanese Circulation Journal-english Edition | 1987
Makoto Akaishi; Toru Ikegawa; Hitoshi Yokozuka; Yasuhiko Nishikawa; Shunnosnke Handa; Yoshiro Nakamura