EFFECTS OF HYPERTROPHY ON THE CORONARY CIRCULATION

在过去的十年里，大量的知识， 心肌和左心室生长之间复杂的相互作用， 被积累。 虽然现在普遍认为，许多类型的 心脏肥大显著地并且不利地改变冠状动脉 肥厚型心肌病的循环和电生理特点 心肌，许多重要领域仍有待探索。 这项建议 具有四个主要目标：1）定义冠状动脉中的一个或多个段 动脉微血管负责增加最小冠状动脉 当左心室肥大发生时观察到的血管阻力 对全身性高血压的反应。 这些研究将采用一种独特的 测量动脉内微血管压力和直径的技术 在跳动的左心室中尺寸小至100微米; 2）以确定 如果继发于肾性高血压的左心室肥大损害了 成熟冠状动脉侧支血管的发育。 因为冠状动脉的生长 局限于肥厚的心室，我们假设冠状动脉 侧支生长也可能受损; 3）评估 自主神经张力和左心室压增加 正常人缺血心肌的电生理特征 和肥大的心脏;和4）研究反应性心脏病的病理生理学。 急性心肌梗死患者出现的心肌肥厚。 在 这些研究将测量左心室质量随时间的变化 用独特而精确的方法定义左心室质量（电影 计算机断层扫描）。 此外，血管造影正常的冠状动脉储备 既往心肌梗死患者中灌注肥大肌肉的血管 将使用冠状动脉内多普勒导管研究梗死， 冠状动脉内罂粟碱最大冠状动脉扩张。 总的来说， 这四组研究将进一步加深我们对 心脏肥大对冠状动脉循环和血管的复杂影响 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.