School of Mathematics and Statistics, University of Glasgow, UK.
Centre for Perceptual and Interactive Intelligence, The Chinese University of Hong Kong, Hong Kong, China.
Math Biosci Eng. 2022 Feb 16;19(4):4101-4119. doi: 10.3934/mbe.2022189.
This work accompanies the first part of our study "effects of dispersed fibres in myocardial mechanics: Part I passive response" with a focus on myocardial active contraction. Existing studies have suggested that myofibre architecture plays an important role in myocardial active contraction. Following the first part of our study, we firstly study how the general fibre architecture affects ventricular pump function by varying the mean myofibre rotation angles, and then the impact of fibre dispersion along the myofibre direction on myocardial contraction in a left ventricle model. Dispersed active stress is described by a generalised structure tensor method for its computational efficiency. Our results show that both the myofibre rotation angle and its dispersion can significantly affect cardiac pump function by redistributing active tension circumferentially and longitudinally. For example, larger myofibre rotation angle and higher active tension along the sheet-normal direction can lead to much reduced end-systolic volume and higher longitudinal shortening, and thus a larger ejection fraction. In summary, these two studies together have demonstrated that it is necessary and essential to include realistic fibre structures (both fibre rotation angle and fibre dispersion) in personalised cardiac modelling for accurate myocardial dynamics prediction.
本工作是我们的研究“分散纤维对心肌力学的影响：第一部分被动反应”的第一部分的补充，重点研究心肌主动收缩。现有研究表明，肌纤维结构在心肌主动收缩中起着重要作用。在我们的研究的第一部分之后，我们首先通过改变平均肌纤维旋转角度来研究一般纤维结构如何影响心室泵功能，然后研究纤维沿着肌纤维方向的分散对左心室模型中心肌收缩的影响。分散的主动应力通过广义结构张量方法来描述，以提高其计算效率。我们的结果表明，肌纤维旋转角度及其分散度都可以通过在周向和长轴方向重新分配主动张力，显著影响心脏泵功能。例如，较大的肌纤维旋转角度和较高的沿片法线方向的主动张力可导致收缩末期容积明显减小和纵向缩短增加，从而射血分数更高。总之，这两项研究表明，在个性化心脏建模中纳入现实的纤维结构（纤维旋转角度和纤维分散度）对于准确预测心肌动力学是必要且重要的。
