Structure‐based finite strain modelling of the human left ventricle in diastole

Abstract

A copy can be downloaded for personal non-commercial research or study, without prior permission or charge Content must not be changed in any way or reproduced in any format or medium without the formal permission of the copyright holder(s) SUMMARYFinite strain analyses of the left ventricle provide important information on heart function and have the potential to provide insights into the biomechanics of myocardial contractility in health and disease. Systolic dysfunction is the most common cause of heart failure; however, abnormalities of diastolic function also contribute to heart failure, and are associated with conditions including left ventricular hypertrophy and diabetes. The clinical significance of diastolic abnormalities is less well understood than systolic dysfunction, and specific treatments are presently lacking. To obtain qualitative and quantitative information on heart function in diastole, we develop a three-dimensional computational model of the human left ventricle that is derived from noninvasive imaging data. This anatomically realistic model has a rule-based fibre structure and a structure-based constitutive model. We investigate the sensitivity of this comprehensive model to small changes in the constitutive parameters and to changes in the fibre distribution. We make extensive comparisons between this model and similar models that employ different constitutive models, and we demonstrate qualitative and quantitative differences in stress and strain distributions for the different constitutive models. We also provide an initial validation of our model through comparisons to experimental data on stress and strain distributions in the left ventricle.

Computational modelling of left-ventricular diastolic mechanics: Effect of fibre orientation and right-ventricle topology

“…Diastolic modelling were carried out using 'Fung-type' law (Usyk et al, 2000) and 'pole-zero' law (Stevens et al, 2003) to incorporate material orthotropy. The material parameters in these orthotropic models were merely used as weighting factors, rather than any physical significance (Göktepe et al, 2011), and some of these parameters were highly correlated (Wang et al, 2013). Recently, Holzapfel and Ogden (2009) developed a constitutive law that considered the locally orthotropic tissue architecture and the parameters of this model were closely related to the characteristic microstructure of myocardium.…”

“…Recently, Holzapfel and Ogden (2009) developed a constitutive law that considered the locally orthotropic tissue architecture and the parameters of this model were closely related to the characteristic microstructure of myocardium. With the advancement in imaging modalities over the years, patient-specific human heart geometry, created from MRI images, was used for the simulation (Wang et al, , 2013. However, bi-ventricular modelling of human heart for passive inflation mechanics is very limited due to complexity of the ventricular geometry (Table 1).…”

Towards causally cohesive genotype–phenotype modelling for characterization of the soft-tissue mechanics of the heart in normal and pathological geometries

“…Gjuvsland et al [41] argued that systems with monotone doseresponse relationships tend to produce more additive GP maps than unimodal or other non-monotone relationships. The low amount of interaction effects in figure 4 suggests that findings from earlier separate studies of stiffness [22], geometry [23] and fibre structure [24] will often remain valid under different conditions, including different genetic backgrounds and more complex and realistic genetic parameter variation. The details of the parameter-to-phenotype mapping will depend on the choice of constitutive law, as they use different parametrizations to capture different aspects of material behaviour.…”

“…Specifically, we model the passive filling phase (late diastole) of the left ventricle, in which many individual factors have been studied previously [22][23][24][25]. The mechanics in this phase are relatively simple owing to the absence of active contraction, yet the strain and elastic energy stored in diastole gives our conclusions some relevance to the later phases of the heartbeat as well.…”

Computational modeling of the electromechanical response of a ventricular fiber affected by eccentric hypertrophy

“…where a, b, a f and b f are fixed parameters taken from [23], whilst I e 1 = C e : I and I e 4f = a T f C e a f are the elastic invariants [4,19]. We choose a transversely isotropic constitutive law because, in this work, the fiber has equal material properties in any direction transverse to a f .…”