ANALYSIS OF SYSTOLIC BULGING - MECHANICAL CHARACTERISTICS OF ACUTELY ISCHEMIC MYOCARDIUM IN THE CONSCIOUS DOG
ANALYSIS OF SYSTOLIC BULGING - MECHANICAL CHARACTERISTICS OF ACUTELY ISCHEMIC MYOCARDIUM IN THE CONSCIOUS DOG
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DOI：
10.1161/01.res.58.2.209
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发表时间：
1986-02-01
影响因子：
20.1
通讯作者：
HELFANT, RH
中科院分区：
文献类型：
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作者：
AKAISHI, M;WEINTRAUB, WS;HELFANT, RH
为了确定急性冠状动脉闭塞后影响局部节段运动的机械因素，我们研究了七只清醒的狗，用sonomicrimeters。通过抽取500 ml血液和输注800 ml血液改变加载条件。为了表达节段性运动，计算收缩期缩短百分比、收缩期延长百分比和舒张早期缩短百分比。抽血降低了左心室前负荷，增加了收缩期延长百分比（从6.9 . ±. 3.1%至9.9 .+-。3.5%）和舒张早期缩短（12.9 . ±. 5.3%至16.6 .+-。5.3%），收缩期缩短百分比降低。输血增加了左心室前负荷，降低了收缩期延长百分比（至5.2 ± 0.05）。1.8%）和舒张早期缩短（8.8 . ±. 2.9%），收缩期缩短百分比增加。负荷操作不改变局部心肌血流量。在急性缺血心肌中，张力-长度环在等容收缩期呈指数上升，在收缩后等容舒张期呈几乎叠加的指数下降，与弹性材料所见的基本被动运动相一致。加载条件的变化对拉伸长度曲线的影响很小。曲线的均匀性及其指数形状解释了收缩期膨胀和节段性运动的负荷依赖性。结果表明，收缩期心肌膨出依赖于张力-长度曲线的顺应部分引起的前负荷张力的变化，而等容舒张期缺血心肌的缩短是一种完全被动的现象。
To determine the mechanical factors affecting regional segmental motion after acute coronary occlusion, we studied seven conscious dogs, instrumented with sonomicrometers. Loading conditions were changed by the withdrawal of 500 ml of blood and the transufusion of 800 ml of blood. To express segmental motion, percent systolic shortening, percent systolic elongation, and early diastolic shortening were calculated. Blood withdrawal decreased left ventricular preload, increased percent systolic elongation (from 6.9 .+-. 3.1% to 9.9 .+-. 3.5%) and early diastolic shortening (12.9 .+-. 5.3% to 16.6 .+-. 5.3%), and decreased percent systolic shortening. Blood transfusion increased left ventricular preload, decreased percent systolic elongation (to 5.2 .+-. 1.8%) and early diastolic shortening (8.8 .+-. 2.9%), and increased percent systolic shortening. Manipulation of loading did not change regional myocardial blood flow. In acutely ischemic myocardium, the tension-length loop showed an exponential upstroke during isovolumic systole and a nearly superimposed exponential downstroke during the isovolumic relaxation phase after systole, compatible with essentially passive movement as seen with an elastic material. The changes in loading conditions affected the tension-length curve to a very minor extent. The uniformity of the curve and its exponential shape explain the load-dependency of systolic bulging and segmental motion. It is cncluded that systolic bulging depends on the change in the preload tension due to the compliant portion of tension-length curve, and that shortening of ischemic myocardium during the isovolumic relaxation phase is a completely passive phenomenon.