The breakdown of cardiac self-organization leads to heart diseases and failure, the number one cause of death worldwide. Within the traditional time-varying elastance model, cardiac self-organization and breakdown cannot be addressed due to its inability to incorporate the dynamics of various feedback mechanisms consistently. To face this challenge, we recently proposed a paradigm shift from the time-varying elastance concept to a synergistic model of cardiac function by integrating mechanical, electric and chemical activity on micro-scale sarcomere and macro-scale heart. In this paper, by using our synergistic model, we investigate the mechano-electric feedback (MEF) which is the effect of mechanical activities on electric activity—one of the important feedback loops in cardiac function. We show that the (dysfunction of) MEF leads to various forms of heart arrhythmias, for instance, causing the electric activity and left-ventricular volume and pressure to oscillate too fast, too slowly, or erratically through periodic doubling bifurcations or ectopic excitations of incommensurable frequencies. This can result in a pathological condition, reminiscent of dilated cardiomyopathy, where a heart cannot contract or relax properly, with an ineffective cardiac pumping and abnormal electric activities. This pathological condition is then shown to be improved by a heart assist device (an axial rotary pump) since the latter tends to increase the stroke volume and aortic pressure while inhibiting the progression (bifurcation) to such a pathological condition. These results highlight a nontrivial effect of a mechanical pump on the electric activity of the heart.

中文翻译：

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心脏功能协同模型中的机电效应和心脏辅助装置

心脏自组织的崩溃会导致心脏病和衰竭，这是全球范围内第一大死亡原因。在传统的时变弹性模型中，由于心脏的自组织和崩溃无法始终如一地纳入各种反馈机制的动力学，因此无法解决。为了应对这一挑战，我们最近提出了一种方法，它通过整合微型肌瘤和宏观心脏上的机械，电和化学活动，从时变弹性概念转变为心脏功能的协同模型。在本文中，通过使用我们的协同模型，我们研究了机械电反馈（MEF），这是机械活动对电活动的影响-心脏功能的重要反馈回路之一。我们显示（功能障碍）MEF会导致各种形式的心律失常，例如，导致电活动，左心室容积和压力的振荡过快，过慢或通过周期性倍增的分叉或异位刺激引起异常波动频率。这可能会导致病理状况，使人联想到扩张型心肌病，在这种情况下，心脏无法正常收缩或松弛，心脏抽动无效且电活动异常。然后示出了通过心脏辅助装置（轴向旋转泵）来改善这种病理状况，因为后者倾向于增加搏动量和主动脉压，同时抑制了这种病理状况的发展（分叉）。