Left ventricular geometry during partial and complete coronary occlusion in the conscious dog

Hess, Otto M.; Osakada, Genta; Lavelle, John F.; Gallagher, Kim P.; Kemper, W S; Ross, John

doi:10.1016/0167-5273(82)90064-x

Cited by 6 publications

(3 citation statements)

References 25 publications

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“…Kumada et al (1979) found no increase in nonischemic area segment shortening after a brief 1-minute coronary artery occlusion. Hess et al (1982) found no change in nonischemic area wall thickening after a 2-minute occlusion, although in this study left ventricular end-diastolic pressure did not increase. In contrast, Theroux et al (1976) found a significant increase in left ventricular end-diastolic pressure and nonischemic area segment shortening after a 2-minute coronary artery occlusion.…”

Section: Discussioncontrasting

confidence: 43%

“…When an apparent hyperfunction in the nonischemic area is noted in the conscious animal, the magnitude of this change may be less than in the anesthetized preparation (Theroux et al, 1976). Furthermore, with similar periods of coronary artery occlusion, wall thickening measurements may not yield precisely the same information as segment shortening measurements (Theroux et al, 1976;Sasayama et al, 1981;Hess et al, 1982). Therefore, extrapolation of our results to the conscious animal and to more prolonged periods of ischemia must be made cautiously.…”

Section: Discussionmentioning

confidence: 84%

“…Acute ischemia in the conscious animal also is associated with a significant increase in heart rate (Heyndrickx et al, 1975;Theroux et al, 1976Theroux et al, , 1977Kumada et al, 1979;Savage et al, 1981;Sasayama et al, 1981;Hess et al, 1982), a reflex response which was blunted in our anesthetized open-chest preparation. Although such reflex changes may modify the magnitude of the interaction between ischemic and nonischemic areas, the qualitative findings in the current study were not significantly influenced by adrenergic factors.…”

Section: Discussionmentioning

confidence: 99%

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Mechanisms of augmented segment shortening in nonischemic areas during acute ischemia of the canine left ventricle.

Lew¹,

Chen²,

Guth³

et al. 1985

Circulation Research

122

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SUMMARY. To examine the interaction between normal and nonischemic areas of the left ventricle during acute ischemia, we implanted midwall ultrasonic segment length gauges in the ischemic zone and in nonischemic areas of the canine left ventricle. During acute ischemia, enddiastolic pressure and segment length in the nonischemic areas increased. There was no change from control in the segment length at the time of aortic valve opening and closure. Thus, in nonischemic areas, total segment shortening, as measured by the percent change in segment length from the time of end-diastole to aortic valve closure, increased. This was due to an increase in isovolumic shortening (end-diastole to aortic valve opening) with no change in ejection shortening (aortic valve opening to closure). The progressive increase in isovolumic shortening in nonischemic areas over time was directly paralleled by the progressive development of the isovolumic lengthening or bulge in the ischemic zone. Nonischemic areas, whether adjacent, on the opposite wall, or distant to the ischemic zone, all behaved similarly. Adrenergic blockade did not qualitatively alter these findings. We conclude that acute ischemia induces a mechanical disadvantage which is greater than just the loss of contractile function by the ischemic segment. Despite the apparent hyperfunction of nonischemic areas, the increased total segment shortening is expended in stretching the ischemic zone during isovolumic systole. As a result, there is no significant "compensatory' increase in ejection shortening in nonischemic areas. The results from the present study indicate that augmented total segment shortening in nonischemic areas is due ' to a combination of the Frank-Starling mechanism and regional intraventricular unloading of the nonischemic into the ischemic areas. (Circ Res 56: 351-358, 1985)

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Section: Discussioncontrasting

confidence: 43%