Analysis of Coronary Slosh Phenomenon by Needle-probe CCD Microscope and Molecular Blood Flow Tracer

众所周知，心内膜下比心内膜下更容易缺血是缺血性心脏病的一个重要病理生理特征。然而，心内膜下缺血易感性的机制尚不完全清楚。我们认为冠状动脉晃动现象，即血液在冠状动脉近端和心内小动脉之间来回运动，至少部分是心内膜下易缺血的原因。为了了解与冠状动脉晃动现象相关的微血管行为的本质，我们采用带CCD摄像机的针探针视频显微镜测量了心脏周期跳动时犬心脏心肌微血管的直径。我们还试图通过引入一种新的分子血流示踪分析来了解其与心肌血流空间分布的关系，并评估α -肾上腺素能激活对冠状动脉晃动现象的影响。收缩期心外膜冠状动脉直径增大，而心内膜和中膜冠状动脉直径减小约20%。这些结果表明，心肌收缩对心内小动脉血管的压迫可能是冠状动脉晃动现象的机械原因，而心肌收缩在心内膜下比在心内膜下更大。心肌血流分布分析表明，在生理状态下，心肌微循环的调节单位为500 ~ 600 μ m，心肌深层相邻区域血流的相关性大于浅层。α -肾上腺素能激活可减少冠状动脉晃动现象，提示α -肾上腺素能活动有助于将血液输送到心内膜下，而心内膜下在运动或精神紧张时因α -肾上腺素能驱动增加而缺血的风险最大。少

It is well known as an important pathophysiological feature of the ischemic heart disease that subendocardium is more susceptible to ischemia than subepicardium. However, the mechanism which is responsible for the subendocardial vulnerability to ischemia is not fully understood yet. We considered that coronary slosh phenomenon, i.e., the to-and-fro movement of the blood between proximal portion of the coronary artery and intramyocardial arterioles would at least partially be responsible to the subendocardial vulnerability to ischemia. To understand the nature of the microvascular behavior in relation to the coronary slosh phenomenon, we measured the diameters of the myocardial microvessels of the beating canine heart during cardiac cycle by introducing a needleprobe videomicroscope with a CCD camera. We also aimed to understand its relation to the spatial distribution of the myocardial blood flow by introducing a novel molecular blood flow tracer analysis, and to evaluate the influence … More of alpha-adrenergic activation to the coronary slosh phenomenon.The coronary arteriolar diameter of epicardium increased during systole, whereas those of endocardium and midmyocardium decreased by about 20%. These results indicate that the compression of the intramyocardial arterioles vessels due to myocardial contraction, which is supposed to be greater in the subendocardium than in the subepicardium, would be the mechanical cause of the coronary slosh phenomenon. Analysis of the myocardial blood flow distribution showed that during physiological condition, regulation unit of myocardial microcirculation would be 500-600 mum and the correlation between adjacent regional flows of the deep myocardial layr is larger than that of superficial myocardial layr.Alpha-adrenergic activation reduced the coronary slosh phenomenon, suggesting that the alpha-adrenergic activity plays a role in distributing the blood favorably toward the subendocardium, where is at greatest risk of ischemia on increased alpha-adrenergic drive during exercise or mental stress. Less