Cardiac muscle cells can exhibit complex patterns including irregular behaviour such as chaos or (chaotic) early afterdepolarisations (EADs), which can lead to sudden cardiac death. Suitable mathematical models and their analysis help to predict the occurrence of such phenomena and to decode their mechanisms. The focus of this paper is the investigation of dynamics of cardiac muscle cells described by systems of ordinary differential equations. This is generically performed by studying a Purkinje cell model and a modified ventricular cell model. We find chaotic dynamics with respect to the leak current in the Purkinje cell model, and EADs and chaos with respect to a reduced fast potassium current and an enhanced calcium current in the ventricular cell model — features that have been experimentally observed and are known to exist in some models, but are new to the models under present consideration. We also investigate the related monodomain models of both systems to study synchronisation and the behaviour of the cells on macro-scale in connection with the discovered features. The models show qualitatively the same behaviour to what has been experimentally observed. However, for certain parameter settings the dynamics occur within a non-physiological range.

心肌细胞可表现出复杂的模式，包括不规则行为，例如混沌或（混沌）早期去极化（EAD），这会导致心脏猝死。合适的数学模型及其分析有助于预测此类现象的发生并解码其机理。本文的重点是研究常微分方程组描述的心肌细胞动力学。通常通过研究Purkinje细胞模型和改良的心室细胞模型来执行此操作。我们在Purkinje细胞模型中发现了关于泄漏电流的混沌动力学，在心室细胞模型中发现了关于快速钾电流减少和钙电流增加的EAD和混沌现象-实验上已经观察到并且已知存在这种特征在某些型号中 但对于目前正在考虑中的模型来说是新的。我们还研究了两个系统的相关单域模型，以研究与发现的特征相关的同步和宏观尺度上细胞的行为。该模型在质量上显示出与实验观察到的相同的行为。但是，对于某些参数设置，动力学发生在非生理范围内。