Effects of Changes in Afterload on Regional  Wall Motion in Acute Ischemic Canine Heart.

Sakuma, Masashi; Shirato, Kunio; Oikawa, Yoshiohika; Katoh, Atsushi; Nakagawa, Makoto; Ishigaki, Hidehiko; Takishima, Tamotsu

doi:10.1620/tjem.169.31

Cited by 1 publication

(4 citation statements)

References 24 publications

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“…These results seem to differ from those of the previous reports (Akaishi et al 1985;Noma et al 1988a, b;Ishikawa et al 1993;Sakuma et al 1993) which showed that the increase of the isovolumetric shortening in the non-ischemic region reflected the increase of the isovolumetric bulging in the ischemic region, both in the preload change and in the afterload change. The changes of the end-diastolic relations between the non-ischemic and ischemic regions partly affected the relationship between these two regions in the isovolumetric phase.…”

Section: Regional Wall Motion In the Isovolumetric Phasecontrasting

confidence: 99%

“…When the heart rate increased, the end-diastolic length (preload) were decreased but, at least, the left ventricular pressure at the timing of aortic valve opening (afterload) was not decreased. On the basis of previously reported data on the effect of preload and afterload (Lew and Ban-Hayashi 1985;Ishikawa et al 1993;Sakuma et al 1993), tachycardia may precede the increase of the shortening in the non-ischemic region during the isovolumetric shortening phase. However, differing from this estimation, the shortening of the nonischemic region showed no significant change with the increase in heart rate.…”

Section: Regional Wall Motion In the Isovolumetric Phasementioning

confidence: 84%

“…On the other hand, the increase in the bulging in the ischemic region with the increase in heart rate can be partly explained by the reduction of the end-diastolic length (Ishikawa et al 1993). In the isovolumetric contraction phase, the increment of the shortening in the non-ischemic region has been explained by the augmentation of bulging in the ischemic region that is increased when the preload is decreased or the afterload increased (Lew and Ban-Hayashi 1985;Noma et al 1988a;Ishikawa et al 1993;Sakuma et al 1993). But when the heart rate increased, the increase of the bulging in the ischemic region was not accompanied by shortening in the non-ischemic region.…”

Section: Regional Wall Motion In the Isovolumetric Phasementioning

confidence: 99%

“…In regional ischemic heart, the effects of changes in preload, afterload and contractile state on regional wall motion have been reported (Akaishi et al 1985;Lew and Ban-Hayashi 1985;Noma et al 1988a, b;Ishikawa et al 1993;Sakuma et al 1993). It has been shown that the degree of isovolumetric shortening in the non-ischemic region reflects the degree of paradoxical systolic expansion in the ischemic myocardium.…”

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confidence: 99%

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Effects of Tachycardia on Regional Wall Motion in Acute Ischemic Canine Heart

Yamamoto

Sakuma

Hozawa

et al. 2004

Tohoku J. Exp. Med.

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Tachycardia accompanies the preload reduction. Our aim is to assess the effect of the heart rate change on wall motion in ischemic heart. In 8 dogs with occlusion of left anterior descending artery, we changed the heart rate (heart rate 90, 120, and 150 beats/minute) after using UL-FS49, a selective bradycardic agent, with atrial pacing. Preload was changed by inferior vena caval occlusion at a heart rate of 90 beats/minute. With either an increase in heart rate or an inferior vena caval occlusion, the end-diastolic length was decreased, but the end-diastolic length relationships between the non-ischemic and the ischemic region made different lines from those of the heart rate change and inferior vena caval occlusion. When increasing the heart rate, isovolumetric shortening was unchanged in the non-ischemic region with more expansion in the ischemic region. While inferior vena caval occlusion at a heart rate of 90 beats/minute, isovolumetric shortening was increased in the non-ischemic region, with more expansion in the ischemic region. Both in tachycardia and by the inferior vena caval occlusion, ejectional shortenings decreased in the non-ischemic and ischemic regions. Our results suggest that, in ischemic heart, tachycardia changes both in the end-diastolic length relationship between the nonischemic and the ischemic region and at the isovolumetric contraction phase. The changes seem to be not only due to the inferior vena caval occlusion, but also due to tachycardia itself. heart rate; preload; isovolumetric phase; ischemic region; UL-FS49

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Section: Regional Wall Motion In the Isovolumetric Phasecontrasting

confidence: 99%

Section: Regional Wall Motion In the Isovolumetric Phasementioning

confidence: 84%