Effects of ischemia on left ventricular regional function in the conscious dog.
Effects of ischemia on left ventricular regional function in the conscious dog.
复制标题
缺血对清醒狗左心室区域功能的影响。
DOI：
10.1152/ajpheart.1981.240.3.h413
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Anderson,RW
中科院分区：
文献类型：
--
作者：
Edwards2nd,CH;Rankin,JS;McHale,PA;Ling,D;Anderson,RW
对7只清醒训练犬长期植入脉冲传输超声换能器的左心室的三维区域几何形状进行了评估。测量左冠状动脉前降支分布的短轴和长轴长度及壁厚；用高保真测压仪测量跨壁压(TMP)。分别在对照组、S 30min和缺血30min后记录数据。维度被归一化为从零TMP(LO)处的长度开始的分数延伸。计算了动态立方体质量，并在对照和缺血状态下在整个心动周期中保持不变，尽管计算的质量在缺血期间平均减少了5%。急性冠脉闭塞后，指数型舒张压-内径关系的斜率常数增加，表明局部心肌硬度随缺血时间的延长而增加。冠状动脉闭塞还与长轴和短轴测量的LO增加以及LO壁厚的减少有关。这些发现与缺血引起的局部心肌的可塑性变形定义为蠕变是一致的。因此，急性缺血导致局部收缩功能下降，诱发心肌蠕动，并导致局部心肌硬度立即和持续增加。
Three-dimensional regional geometry of the left ventricle was assessed in seven conscious trained dogs chronically implanted with pulse-transit ultrasonic-dimension transducers. Minor and major axis segment lengths and wall thickness were measured in the distribution of the left anterior descending coronary artery; transmural pressure (TMP) was measured with high-fidelity micromanometers. Data were recorded during the control state and following 30 s and 30 min of ischemia. Dimensions were normalized as a fractional extension from the length at zero TMP (Lo). Dynamic cube mass was calculated and remained constant throughout the cardiac cycle in both control and ischemic states, although the calculated mass decreased by an average of 5% during ischemia. The slope constants of the exponential diastolic pressure-dimension relationship increased following acute coronary occlusion indicating increases in regional myocardial stiffness with increasing periods of ischemia. Coronary occlusion also was associated with an increase in the Lo measurements in the major and minor axis dimensions and a decrease in the wall thickness Lo. These findings are consistent with an ischemia-induced plastic deformation of the regional myocardium defined as creep. Thus, acute ischemia results in a decline of regional systolic function, induces myocardial creep, and causes an immediate and sustained increase in regional myocardial stiffness.