Left ventricular systolic dynamics in terms of its chamber mechanical properties.
Left ventricular systolic dynamics in terms of its chamber mechanical properties.
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左心室收缩动力学的腔室机械特性。
DOI：
10.1152/ajpheart.1983.245.1.h110
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Weber,KT
中科院分区：
文献类型：
--
作者：
Shroff,SG;Janicki,JS;Weber,KT
为了确定左心室作为泵的力学特性，建立了左心室收缩动力学的数学模型。最初，该模型由三个元素组成，即弹性、阻力和惯性。然而，三个实验的结果表明，惯性分量与其他两个分量相比可以忽略不计。弹性和阻力的功能形式是通过应用流脉冲响应技术来确定一个等体积跳动，孤立的犬心脏。三个实验的结果表明，收缩弹性和阻力分别可以用时间的三阶多项式和瞬时心室压的线性函数来表示。然后通过计算一个心脏周期内左室射出的LVP、容积和流量数据的收缩弹性和阻力来测试简化模型。共225组（10组）舒张末期容积（EDV）、射血压力（EP）、心率（HR）和收缩状态（CS）进行评估。结果表明：1)弹性函数对EDV和EP的变化不敏感，是CS和HR的函数；2)电阻-压力线性关系对EDV、EP、HR和CS的变化不敏感；3)该模型能够“前瞻性”地根据弹射拍的数据预测LV等容压力。由此建立了左室收缩动力学模型，该模型可用于计算左室弹射的固有腔室力学特性，即弹性和阻力。
To determine the mechanical properties of the left ventricle (LV) as a pump, a mathematical model of its systolic dynamics was developed. Initially the model consisted of three elements, i.e., elastance, resistance, and inertance. Results from three experiments, however, indicated that the inertial component was negligible compared with the other two components. The functional forms of elastance and resistance were determined by applying the flow-pulse response technique to an isovolumetrically beating, isolated canine heart. Results from three experiments indicated that the systolic elastance and resistance can be represented by a third-order polynomial in time and a linear function of instantaneous ventricular pressure (LVP), respectively. The simplified model was then tested by calculating the systolic elastance and resistance from LVP, volume, and flow data of an ejecting LV obtained over a single cardiac cycle. A total of 225 combinations (10 expts) of end-diastolic volume (EDV), ejection pressure (EP), heart rate (HR), and contractile state (CS) were evaluated. The results indicated that 1) the elastance function was insensitive to variations in EDV and EP but was a function of CS and HR; 2) the linear resistance-pressure relationship was insensitive to variations in EDV, EP, HR, and CS; and 3) the model could "prospectively" predict the LV isovolumetric pressure from the data of an ejecting beat. Thus a model of LV systolic dynamics has been established that can be used to calculate the intrinsic chamber mechanical properties, i.e., elastance and resistance, of an ejecting LV.