Linear Relationship Between the Distribution of Thallium‐201 and Blood Flow in Ischemic and Nonischemic Myocardium During Exercise
Linear Relationship Between the Distribution of Thallium‐201 and Blood Flow in Ischemic and Nonischemic Myocardium During Exercise
复制标题
运动时铊-201分布与缺血和非缺血心肌血流量的线性关系
作者：
A. Nielsen;K. Morris;R. Murdock;F. P. Bruno;F. Cobb
本研究的目的是比较心肌缺血和运动生理应激时铊-201的心肌分布和局部心肌血流量。在6只犬中进行了研究，在心房和主动脉中长期植入导管，并在第一边缘分支远端的回旋冠状动脉上植入圈套器。局部心肌血流量测量在安静，休息条件下使用7-10，放射性同位素标记的微球。然后每只狗在跑步机上以5-9英里/小时的速度在50度的坡度上锻炼。运动1分钟后，闭塞冠状动脉回旋支，并注射铊-201和第二标记的微球。运动持续5分钟。然后将狗处死，将左心室切成约80个1-2-g样品，以比较铊-201活性和局部心肌血流量，血流量的最大增加范围为静息对照值的3.3-7.2倍。每只犬的心肌样本中血流量显著降低，低于0.10 ml/min/g。在每只狗中，铊-201分布和直接测量局部心肌血流量之间存在密切的线性关系。线性回归分析表明，每只犬的相关系数为0.98或更大。这些数据表明，在运动的生理应激，心肌分布的铊活动是线性相关的局部心肌血流量在缺血和非缺血区域。
The purpose of this study was to compare the myocardial distribution of thallium-201 and regional myocardial blood flow during ischemia and the physiologic stress of exercise. Studies were carried out in six dogs with chronically implanted catheters in the atrium and aorta and a snare on the circumflex coronary artery distal to the first marginal branch. Regional myocardial blood flow was measured during quiet, resting conditions using 7–10, of radioisotope-labeled microspheres. Each dog was then exercised on a treadmill at speeds of 5–9 mph at a 50 incline. After 1 minute of exercise the circumflex coronary artery was occluded and thallium-201 and a second label of microspheres were injected. Exercise was continued for 5 minutes. The dogs were then sacrificed and the left ventricle was sectioned into approximately 80 1–2-g samples to compare thallium-201 activity and regional myocardial blood flow.The maximum increase in blood flow ranged from 3.3–7.2 times resting control values. Each dog had myocardial samples in which blood flow was markedly reduced, to less than 0.10 ml/min/g. In each dog there was a close linear relationship between thallium-201 distribution and direct measurements of regional myocardial blood flow. Linear regression analyses demonstrated a correlation coefficient of 0.98 or greater in each dog. These data indicate that during the physiologic stress of exercise, the myocardial distribution of thallium activity is linearly related to regional myocardial blood flow in both the ischemic and nonischemic regions.