Experiments on animal hearts (rat, rabbit, guinea pig, etc.) have demonstrated that mechano-calcium feedback (MCF) and mechano-electric feedback (MEF) are very important for myocardial self-regulation because they adjust the cardiomyocyte contractile function to various mechanical loads and to mechanical interactions between heterogeneous myocardial segments in the ventricle walls. In in vitro experiments on these animals, MCF and MEF manifested themselves in several basic classical phenomena (e.g., load dependence, length dependence of isometric twitches, etc.), and in the respective responses of calcium transients and action potentials. However, it is extremely difficult to study simultaneously the electrical, calcium, and mechanical activities of the human heart muscle in vitro. Mathematical modeling is a useful tool for exploring these phenomena. We have developed a novel model to describe electromechanical coupling and mechano-electric feedbacks in the human cardiomyocyte. It combines the 'ten Tusscher-Panfilov' electrophysiological model of the human cardiomyocyte with our module of myocardium mechanical activity taken from the 'Ekaterinburg-Oxford' model and adjusted to human data. Using it, we simulated isometric and afterloaded twitches and effects of MCF and MEF on excitation-contraction coupling. MCF and MEF were found to affect significantly the duration of the calcium transient and action potential in the human cardiomyocyte model in response to both smaller afterloads as compared to bigger ones and various mechanical interventions applied during isometric and afterloaded twitches.

中文翻译：

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用数学模型分析人心肌细胞中的机械钙和机械电反馈。

在动物心脏（大鼠，兔子，豚鼠等）上进行的实验表明，机械钙反馈（MCF）和机械电反馈（MEF）对于心肌自我调节非常重要，因为它们可以调节心肌细胞的收缩功能以适应各种机械负荷以及心室壁异质性心肌节之间的机械相互作用。在针对这些动物的体外实验中，MCF和MEF表现为几种基本的经典现象（例如，负荷依赖性，等距抽动的长度依赖性等）以及钙瞬变和动作电位的各自响应。但是，在体外同时研究人心肌的电，钙和机械活动极其困难。数学建模是探索这些现象的有用工具。我们已经开发出一种新型模型来描述人体心肌细胞中的机电耦合和机电反馈。它结合了人类心肌细胞的“十Tusscher-Panfilov”电生理模型和我们从“叶卡捷琳堡-牛津”模型中提取并针对人类数据进行调整的心肌机械活动模块。使用它，我们模拟了等距和后加载的抽动，以及MCF和MEF对激励-收缩耦合的影响。与较大的后负荷相比，MCF和MEF显着影响人心肌细胞模型中钙瞬变的持续时间和动作电位，与较大的后负荷相比，在等距抽搐和后负荷抽搐期间采用各种机械干预。我们已经开发出一种新型模型来描述人体心肌细胞中的机电耦合和机电反馈。它结合了人类心肌细胞的“十Tusscher-Panfilov”电生理模型与我们从“叶卡捷琳堡-牛津”模型中提取并调整为人类数据的心肌机械活动模块。使用它，我们模拟了等距和后加载的抽动，以及MCF和MEF对激励-收缩耦合的影响。与较大的后负荷相比，MCF和MEF会显着影响人心肌细胞模型中钙瞬变的持续时间和动作电位，与较大的后负荷相比，在等距和后负荷抽搐期间采用各种机械干预。我们已经开发出一种新型模型来描述人体心肌细胞中的机电耦合和机电反馈。它结合了人类心肌细胞的“十Tusscher-Panfilov”电生理模型与我们从“叶卡捷琳堡-牛津”模型中提取并调整为人类数据的心肌机械活动模块。使用它，我们模拟了等距和后加载的抽动，以及MCF和MEF对激励-收缩耦合的影响。与较大的后负荷相比，MCF和MEF显着影响人心肌细胞模型中钙瞬变的持续时间和动作电位，与较大的后负荷相比，在等距抽搐和后负荷抽搐期间采用各种机械干预。