Analysis of coronary slosh phenomenon under coronary stenosis by measurement of blood flow or vasucular diameter in intramyocardial vessels and microvessels

众所周知，心肌缺血常见于心内膜下层。尽管心内膜下层和心外膜下层之间的一些特征差异可能有几个原因，如收缩时的应力、血管外压力、血管数密度和红细胞压积，但还没有给出确切的原因。我们发现，在舒张期流入心内膜下心肌的部分血液在收缩时被心肌压迫而被迫流入心外膜下动脉，这种反向血流量是跨壁分布的重要决定因素。华盛顿大学的费格尔教授还预测，在收缩过程中，血液可能会从心内膜下侧输送到心下侧。本研究的目的是：(1)研究血管扩张化合物和交感神经系统…的作用(2)研究这些化合物是否能使血液均匀分布(抗晃动假说)。用20 MHz超声多普勒测速仪测量麻醉开胸犬鼻中隔动脉的血流速度，以前向血流与后向血流的比值来评价“晃动”的程度。冠状动脉狭窄程度的增加以及向冠状动脉内注入腺苷或硝酸甘油可增强“晃动”效应。研究发现，刺激α-交感神经系统可产生抗晃动作用，其作用与心率呈线性相关。我们还用针头CCD显微镜观察了心内膜下心肌中的冠状动脉微血管，发现动脉直径在收缩过程中缩小了约20%。动脉直径的这种减小被认为是导致“晃动”现象的原因。较少

It is well known that myocardial ischemia is frequently observed in the subendocardial layer. Although several possible reasons have been claimed in relation to some characteristic differences between subendo- and subepi-cardial layers such as stress during systole, extravascular pressure, number density of blood vessels, and hematocrit, no conclusive reason is given yet. We have found that part of blood which flows into the subendocardial myocardium during diastole is forced to flow into the subepicardial artery by myocardial compression during systole and this reversed blood flow volume is an important determinant of transmural distribution. Prof. Feigl from University of Washington also predicted the possibility of blood transport from subendo- to subepi-cardial sides during systole. He then named this phenomenon "slosh" and has claimed its patho-physiological significance.The objectives of this study are (1) to examine the effect of vasodilating compounds and sympathetic nerve syst … More em on the blood transport (slosh) from subendo- to subepi-cardial sides by myocardial compression during systole and the change in this effect in the case of coronary artery stenosis and (2) to study if these compounds can allow uniform blood distribution (anti-slosh hypothesis). The blood flow in septal artery of anesthetized open-chest dog was measured using a 20 MHz ultrasound Doppler velocimeter, and the extent of "slosh" was evaluated as the ratio of forward to backward flows. The effect of "slosh" was augmented by an increase in coronary artery stenosis and by administrations of adenosine or nitroglycerin into a coronary artery. It was found that the stimulation of alpha-sympathetic nerve system led to an anti-slosh effect which was linearly associated with heart rate. We also observed coronary microvessels in the subendocardial myocardium using a needle-probe CCD microscope and found that the arterial diameter decreased about 20 % during systole. This decrease in arterial diameter is considered to cause the "slosh" phenomenon. Less