Conductance to Measure Cardiac Mechanics

描述（申请人的描述逐字）：左 转基因小鼠心室压力-容积关系， 测量收缩性并不是广泛可用的。这项资助的长期目标是 是量化完整小鼠的左心室功能测量 电导提供了一种方法， 心室容积信号。目前可用的瞬时电导 输出是血液和左心室肌肉信号的组合，但是 血容量（仅）是期望的。这个问题可以通过使用两个 同步频率，因为心肌电阻率随频率变化 而血液电阻率则没有。 这项工作将表明，双频电导系统是 优于标准单频系统的上级。结合实验性 研究和数值模型将用于校准血容量 当从组合的血液和肌肉信号中提取时，计算。最后， 仪器仪表的进步被提议将双频系统移动到 闭胸小鼠制剂，以提高商业利益。 通过去除瞬时心肌对容积信号的贡献 在下腔静脉短暂闭塞期间获得，绝对 左心室收缩力的测量将是可用的。这将 拓宽了完整小鼠左心室的血流动力学特征 这是因为压力-体积分析提供了丰富的信息。 拟定商业应用： 双频电导系统将使科学家们能够精确地测量 心血管疾病的转基因小鼠模型的复杂表型，例如 充血性衰竭 左心室功能的定量也将允许药物 产业界进行快速筛选新药的转基因小鼠。 这些的时机 了解所选基因型的表型的研究是理想的人类基因组 项目接近完成;由于人类和小鼠共享一个高度保守的 与心血管功能相关的基因。

DESCRIPTION (Applicant's Description Verbatim): The application of left ventricular pressure-volume relationships to transgenic mice to precisely measure contractility is not widely available. The long-term goal of this grant is to quantify left ventricular function in the intact mouse. Measurement of electrical conductance offers a method to generate an instantaneous left ventricular volume signal. The presently available instantaneous conductance output is a combination of blood and left ventricular muscle signals, but the blood volume (only) is desired. The problem can be solved by using two simultaneous frequencies, since myocardial resistivity varies with frequency while blood resistivity does not. The work will demonstrate that the dual frequency conductance system is superior to the standard single frequency system. A combination of experimental studies and numerical models will be used to calibrate the blood volume calculation when extracted from the combined blood and muscle signal. Finally, advances in instrumentation are proposed to move the dual frequency system to a closed-chest mouse preparation to enhance commercial interest. By removing the instantaneous myocardial contribution to the volume signal obtained during transient occlusion of the inferior vena cava, absolute measures of left ventricular contractility would be available. This would broaden the hemodynamic profile available from the intact murine left ventricle due to the wealth of information provided by pressure-volume analysis. PROPOSED COMMERCIAL APPLICATION: A dual frequency conductance system would allow scientists to precisely measure the complex phenotype of transgenic murine models of cardiovascular disease, such as congestive failure. Quantitation of left ventricular function would also allow the pharmaceutical industry to perform rapid screenting of new durgs in transgenic mice. The timing for these studies to understand the phenotype of selected genotypes is ideal as the Human Genome Project nears completion; and since humans and mice share a subset of highly conserved genes related to cardiovascular function.