LEFT VENTRICULAR-ARTERIAL COUPLING

左心室-动脉耦合

• 批准号: 3360529
• 负责人: William C. Little
• 金额: $ 18.06万
• 依托单位: WAKE FOREST UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-01-01 至 1994-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3360529
• 关键词: cardiovascular disorder; coronary vasodilator; dogs; exercise; heart failure; heart ventricle; intracardiac pressure; intracardiac volume; rest; vascular resistance

The performance of the cardiovascular system depends on the interaction of its components. We propose to investigate the coupling of the left ventricle (LV) and arterial systems in conscious animals with intact reflexes at rest, during exercise, and with depressed LV performance. The analysis of LV and arterial pressure (P)-volume (V) relations to be used in these studies is based on previous observations in the isolated LV ejecting into a model of the arterial system. These concepts have not been evaluated in the circulation of intact, conscious animals and the effects of exercise and clinically important disease processes have not been previously investigated. The following specific hypotheses will be evaluated. Hypothesis 1: The stroke volume (SV) and the LV end-systolic P (PES) are linearly related over the physiologically relevant range. The slope of this relation, EA, is the effective elastance of the arterial system, and is primarily determined under most circumstances by the heart rate and total peripheral vascular resistance. Hypothesis 2: LV stroke work is maximal when end-systolic elastance of the LV (EES) is equal to EA, while mechanical efficiency (the ratio of arterial stroke work to total pressure-volume area, SW/PVA) is maximum when EES is greater than EA. Hypothesis 3: The normal cardiovascular system operates at rest with EES slightly greater than EA, intermediate between points for maximum SW and mechanical efficiency. Hypothesis 4: During exercise, the LV and arterial system function closer to the point of maximum mechanical efficiency with EES > EA; similar increases in heart rate produced by pacing at rest result in suboptimal matching with EES < EA, Hypotheses 5 and 6: When LV function is depressed by rapid pacing induced heart failure or coronary occlusion, the coupling of the LV and arterial system is not optimal, as EA > EES, but can be returned toward optimal by decreasing EA using vasodilators. Hypothesis 1 will be evaluated both in an anesthetized, open-chest preparation in which stroke volume can be precisely controlled by right heart bypass in conscious dogs. The other hypotheses will be evaluated by studying conscious dogs previously instrumented to measure LV pressure and volume. EES will be determined as the slope of the LV end- systolic pressure-volume relation produced by varying LV P and V by transient caval occlusions. EA will be determined as PES/SV. These studies will supply important new information on the coupling of the LV and arterial system of the conscious animal with intact reflexes at rest, during exercise, and following depression of LV performance. These studies may lead to rational interventions to improve pump function in patients with common cardiovascular diseases.

心血管系统的表现取决于以下因素的相互作用 它的组件。我们建议研究左翼的耦合 清醒状态下完好无损动物的左心室和动脉系统 安静时、运动时和左心室表现低落时的反射。这个 左心室与动脉压(P)-容量(V)关系的分析 这些研究是基于先前观察到的孤立的LV射出 变成动脉系统的模型。这些概念还没有 在完整的、有意识的动物的循环中进行评估及其影响 运动和临床上重要的疾病过程还没有 之前被调查过。以下是具体的假设 已评估。假设1：每搏量(SV)和左心室收缩末期 P(PES)在生理相关范围内呈线性相关。这个 这个关系的斜率Ea是动脉的有效弹性 系统，在大多数情况下主要由心脏决定 心率和总外周血管阻力。假设2：左室卒中 当LV的收缩末期弹性(EES)等于Ea时做功最大， 而机械效率(动脉每搏功与总作功的比率 当EES大于Ea时，压力-体积面积(Sw/PVA)最大。 假设3：正常的心血管系统在EES的静息状态下运行 略大于EA，介于最大Sw和 机械效率。假设4：在运动中，左心室和动脉 系统功能更接近最大机械效率点 EES&GT；EA；安静时起搏产生的心率增加类似的结果 在EES&lt；EA次优匹配中，假设5和6：当LV 快速起搏导致心力衰竭或冠状动脉病变时功能受抑 闭塞，左室与动脉系统的耦合不是最理想的，如电针 &gt；EES，但可以通过使用减少EA来使其返回最优 血管扩张剂。 假设1将在麻醉开胸两种情况下进行评估 可用右手精确控制冲量的准备工作 清醒狗的心脏搭桥术。其他假设将通过以下方式进行评估 研究意识清醒的狗之前用仪器测量左心室压力和 音量。EES将被确定为左心室收缩末期的斜率 瞬变空泡变化LV、P、V产生的压力-体积关系 闭塞。EA将被确定为PES/SV。 这些研究将提供重要的新信息，以了解 具有完整反射的清醒动物的左心室和动脉系统 休息，在运动期间，以及在左心室表现低落之后。这些 研究可能导致合理的干预措施，以改善泵的功能 患有常见心血管疾病的患者。