EFFECTS OF HYPERTROPHY ON THE CORONARY CIRCULATION

在过去的十年里，关于 心肌和左心室生长之间复杂的相互作用 已经积累起来了。尽管现在人们普遍认为许多类型的 心肌肥厚对冠状动脉病变有显著的不利影响 肥厚患者的血液循环及电生理特征 对于心肌，许多重要的领域仍有待探索。这项建议 有四个主要目标：1)定义冠状动脉的一个或多个节段 动脉微血管与微冠脉增大有关 左心室肥厚时血管阻力的观察 对系统性高血压的反应。这些研究将采用一种独特的 动脉微血管压力和管径的测量技术 在跳动的左心室中减小到100微米大小；2)确定 如果继发于肾性高血压的左心室肥厚损害 发育成熟的冠脉侧支血管。因为冠状动脉的生长 仅限于肥厚的心室，我们推测冠状动脉 抵押品增长也可能受到损害；3)评估 自主神经张力和左心室压力的增加 正常缺血型心肌的电生理特征 和肥大的心脏；4)研究反应性心肌梗死的病理生理学 急性心肌梗死患者出现的肥大。在……里面 这些研究将随着时间的推移测量左心室质量的变化 以独特而精确的方法定义左心室质量(Cine 计算机断层扫描)。此外，冠状动脉造影正常的冠状动脉储备 既往心肌病患者肥厚肌肉的血管灌流 将使用冠状动脉内多普勒导管和 冠脉内注射罂粟碱最大限度扩张冠状动脉。总而言之， 这四组研究将进一步加深我们对 心肌肥厚对冠脉循环的复杂影响 心肌的电稳定性。

During the past decade, a substantial amount of knowledge concerning the complex interaction between cardiac muscle and left ventricular growth has been accumulated. Although it is now generally held that many types of cardiac hypertrophy significantly and adversely alter the coronary circulation and the electrophysiological characteristics of hypertrophied cardiac muscle, many important areas remain to be explored. This proposal has four major goals: 1) to define the segment or segments in the coronary arterial microvasculature responsible for the increased minimal coronary vascular resistance observed when left ventricular hypertrophy occurs in response to systemic hypertension. These studies will employ a unique technology for measuring microvascular pressure and diameter in arterials down to 100 microns in size in the beating left ventricle; 2) to determine if left ventricular hypertrophy secondary to renal hypertension impairs the development of mature coronary collateral vessels. Because coronary growth is limited in hypertrophied ventricles, we postulate that coronary collateral growth may also be impaired; 3) to assess the effects of autonomic tone and increases in left ventricular pressure on the electrophysiological characteristics of ischemic cardiac muscle in normal and hypertrophied hearts; and 4) to study the pathophysiology of reactive hypertrophy that develops in patients with acute myocardial infarction. In these studies, changes in left ventricular mass will be measured over time with a unique and precise method of defining left ventricular mass (cine computed tomography). Also, coronary reserve in angiographically normal vessels perfusing hypertrophied muscle in patients with previous myocardial infarction will be studied utilizing an intracoronary Doppler catheter and maximal coronary dilation with intracoronary papaverine. In the aggregate, these four groups of studies will further our understanding about the complex effects of cardiac hypertrophy on the coronary circulation and the electrical stability of the myocardium.