EXTRACORPOREAL PERFUSION FOR ACUTE MYOCARDIAL INFARCTION

这一提议将检验这样一种假设，即暂时性左心室 辅助(LVAD)可通过以下方式加速左心功能的恢复 减少左室壁的应力、应变和心肌蠕变 并通过促进急性脑损伤后功能性交界区的恢复 心肌梗死(AMI)。这些变化可能会加速左室重构， 减少最终心室容量并保留更多的收缩功能 急性心肌梗死后除预防持续心肌缺血外， 多支血管疾病患者梗死灶演变过程中的坏死。 该项目将利用声学显微技术精确测量左心室的尺寸 在整个心脏周期中。开发了用于成像LV几何体的方法 2个维度将进一步发展为LV的3维映射 几何图形。这将允许估计区域LV壁应力在 基于直接测量的病理性脑梗塞脑室。 可逆性缺血和左心室扩张的病理生理机制(与 心肌蠕变)将被调查。牙根尖的演变 心肌梗死至心尖部室壁瘤将用左室壁来描述。 机械和02的消耗。这些研究将与进化论进行比较。 回旋性冠状动脉梗死对瘢痕形成的影响及左冠状动脉前降支的作用 LV力学与演化过程中不同时期的O2消耗 两种类型的脑梗塞。研究的重点将放在量化- 邻近和远端心肌的局部应力、应变和蠕变 脑梗塞后，将评估脑室容量和 有和没有左冠状动脉前降支时的收缩性能。这项研究还将确定 局部应力和应变的变化对LVAD的影响 动脉瘤成形术(一种急性改变左心室体积和局部面积的模型 压力)对心室容量、收缩能力和重塑的影响。 以前的工作比较了几种临时的体外循环辅助 不需要开胸手术就可以实施的系统，并确定 LVAD使LV体积和壁应力的减少最显著 在病态的心脏里。因此，该项目试图了解 急性心肌梗死后左心功能恢复的机制 在不开胸的情况下使用左冠状动脉腔内成形术对恢复有良好影响 在脑梗塞后时期。

This proposal will test the hypothesis that temporary left ventricular assistance (LVAD) can accelerate recovery of left ventricular function by reducing left ventricular (LV) wall stresses, strains and myocardial creep and by accelerating recovery of the functional borderzone after acute myocardial infarction (AMI). These changes may accelerate LV remodeling, reduce final Ventricular volumes and preserve more contractile function after AMI in addition to preventing continuing myocardial ischemia and necrosis during evolution of infarcts in patients with multivessel disease. The project will utilize sonomicrometry to accurately measure LV dimensions throughout the cardiac cycle. The method developed to image LV geometry in 2 dimensions will be developed further to 3-dimensional mapping of LV geometry. This will allow estimations of regional LV wall stresses in pathologic infarcted ventricles based on direct measurements. The pathophysiology of reversible ischemia and LV distention (related to myocardial creep) will be investigated. The evolution of an apical myocardial infarct to apical LV aneurysm will be described in terms of LV mechanics and 02 consumption. These studies will be compared to evolution of circumflex coronary artery infarcts to scar and to the effects of LVAD on LV mechanics and 02 consumption at various time periods during evolution of both types of infarcts. The studies will focus on quantitation of - regional stresses, strains and creep in adjacent and remote myocardium after infarction and will assess changes in ventricular volumes and contractility with and without LVAD. The study will also determine the effects of changes in regional stresses and strains produced by LVAD or aneurysm plication (a model to acutely alter LV volume and regional stresses) on ventricular volumes, contractility and remodelling. Previous work compared several temporary extracorporeal circulatory assist systems that could be implemented without thoracotomy and determined that LVAD produces the most dramatic decreases in LV volumes and wall stresses in pathologic hearts. Therefore, the project seeks to understand the mechanisms involved in the recovery of LV function after AMI and to favorably influence this recovery by the use of LVAD without thoracotomy during the postinfarction period.