MODEL FOR LEFT-VENTRICULAR CONTRACTION COMBINING THE FORCE LENGTH VELOCITY RELATIONSHIP WITH THE TIME-VARYING ELASTANCE THEORY
MODEL FOR LEFT-VENTRICULAR CONTRACTION COMBINING THE FORCE LENGTH VELOCITY RELATIONSHIP WITH THE TIME-VARYING ELASTANCE THEORY
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DOI：
10.1016/s0006-3495(84)84265-4
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发表时间：
1984-01-01
影响因子：
3.4
通讯作者：
SIDEMAN, S
中科院分区：
文献类型：
--
作者：
BEYAR, R;SIDEMAN, S
建立了左心室（LV）收缩的球形几何模型。假设单个肌纤维的经典力-长度-速度关系。线性最大压力-体积关系（最大弹性），肌肉收缩力的量度，被进一步扩展为时变函数。这是通过利用机械激活函数来实现的，假设为半个正弦波，来描述激活心肌的时间相关的等距应力。这反过来又产生了时变弹性函数，并代表了肌肉收缩蛋白的瞬时活动。该模型对一组边界条件进行了测试，这些边界条件决定了预载荷、后载荷和肌肉的固有特性，即收缩性。等容收缩、等容收缩和等容松弛的计算结果与预期的左室行为一致。给出并讨论了模拟的预紧力、后紧力和收缩力变化与低压机组性能指标集之间的关系。
A model for the contraction of the left ventricle (LV) is developed for a spheroidal geometry. The classical force-length-velocity relationship for a single muscle fiber is assumed. The linear maximum pressure volume relationship (maximum elastance), a measure of muscle contractility, is further extended into a time-varying function. This is achieved by utilizing a mechanical activation function, assumed as half a sinusoidal wave, to describe the time-dependent isometric stress for the activated cardiac muscle. This, in turn, results in the time-varying elastance function and represents the instantaneous activity of the muscle contractile proteins. The model is tested for a set of boundary conditions that determine preload, afterload and the inherent properties of the muscle, i.e., the contractility. The computed results of the isovolumic contraction, auxotonic contraction and isovolumic relaxation are in agreement with the expected behavior of the LV. The relations between the simulated variations on preload, afterload and contractility, and the set of performance indexes of the LV, are presented and discussed.