Passive myocardial mechanical properties: meaning, measurement, models

Abstract

Passive mechanical tissue properties are major determinants of myocardial contraction and relaxation and, thus, shape cardiac function. Tightly regulated, dynamically adapting throughout life, and affecting a host of cellular functions, passive tissue mechanics also contribute to cardiac dysfunction. Development of treatments and early identification of diseases requires better spatio-temporal characterisation of tissue mechanical properties and their underlying mechanisms. With this understanding, key regulators may be identified, providing pathways with potential to control and limit pathological development. Methodologies and models used to assess and mimic tissue mechanical properties are diverse, and available data are in part mutually contradictory. In this review, we define important concepts useful for characterising passive mechanical tissue properties, and compare a variety of in vitro and in vivo techniques that allow one to assess tissue mechanics. We give definitions of key terms, and summarise insight into determinants of myocardial stiffness in situ. We then provide an overview of common experimental models utilised to assess the role of environmental stiffness and composition, and its effects on cardiac cell and tissue function. Finally, promising future directions are outlined.

Biomimetic design of bioartificial scaffolds for the in vitro modelling of human cardiac fibrosis

“…Stability of polyDOPA/G coating in water-based medium and its high G density were advantageous for optimal support of in vitro cell culture on scaffolds. Cardiac tissue after MI shows patient-specific features depending on fibrosis size (thickness and width) and stage (early or late stage based on the different maturation/remodeling level of the cardiac scar) and is hallmarked by a range of Young’s modulus, from dozens of kPa to few MPa ( Chelnokova et al, 2016 ; Sadeghi et al, 2017 ; Emig et al, 2021 ). Hence, scaffolds for cardiac tissue engineering have been previously designed to display a Young’s modulus varying from 20 kPa to 90 MPa ( Nguyen-Truong et al, 2020 ).…”

Modeling Supraventricular Tachycardia Using Dynamic Computer-Generated Left Atrium

“…Hence, SVT can produce chaotic outcomes that are impossible to predict with great accuracy. 2,5,8,9 There are two basic mechanisms of action that can cause SVT. 2,10,11 The simplest of the two is focal tachycardia.…”

“…The beating heart is a multi-dimensional nonlinear dynamical system that is sensitive to initial conditions. Hence, SVT can produce chaotic outcomes that are impossible to predict with great accuracy 2,5,8,9…”

Simultaneous assessment of radial and axial myocyte mechanics by combining atomic force microscopy and carbon fibre techniques

“…Cellular and subcellular mechanics can be studied using optical tweezers [16][17][18]. The various techniques used to probe cell mechanics have been reviewed in detail elsewhere [19,20]. In spite of this wide range of tools, simultaneous measurements of passive and active single cardiomyocyte mechanics in axial and radial directions have not been reported.…”