Myocardial Material Parameter Estimation - A Comparative Study for Simple Shear

Model Status

This is the original unchecked version of the model imported from the previous CellML model repository, 24-Jan-2006.

Model Structure

Knowledge of the mechanical behaviour of myocardium is pivotal to understanding the mechanisms of defect in regions of the heart. These defects are attributed to causes such as ischaemia, hypertrophy, or remodelling of the collagen microstructure. The study of ventricular mechanics (the analysis of the distribution of strain and stress in myocardium throughout the cardiac cycle) is fundamentally dependant on the accuracy of the specific constitutive laws chosen to represent the three dimensional properties of passive cardiac muscle. In this article, the authors Schmid, Nash, Young and Hunter examine five constitutive material laws and compare them on the following criteria: "goodness of fit", "determinability" and "variability". The aforementioned criteria are utilized to discuss the advantages and disadvantages of the constitutive laws. The constitutive laws considered by the authors are the Costa law, Separated Fung-type law, Pole-Zero law, Tangent Law and the Langevin eight-chain law.

Cardiac mechanics have been modelled over the last 30 years with different material law concepts, (elastic to viscoelastic, phenomenological to microstructurally based). The article provided here aims to provide a brief summary of the attempts to model the passive elastic behaviour of myocardium. One aspect of the material constitutive properties not taken into account in this analysis is the viscoelasticity of myocardial tissue; the primary reason being that at the time of publication the authors felt that there was insufficient data on the passive viscoelastic properties of ventricular myocardium, particularly in regards to the physiological strain rates occurring in vivo (for shear modes of deformation). The authors have instead decided to limit their analysis to the hyperelastic properties only, with emphasis on the shear properties.

The CellML file associated with this article focuses on the Taylor series expansion of the "Tangent Law" developed by Schmid et. al.. This model was implemented in a manner that could be used for performing finite element model simulations on the CMISS software program developed at the Bioengineering Institute, University of Auckland.

For additional information on implementation of cellML files in CMISS, please refer to the following Link.

The complete original paper reference is cited below:

Myocardial Material Parameter Estimation - A Comparative Study for Simple Shear, H. Schmid, M. P. Nash, A. A. Young and P. J. Hunter, 2006. Journal of Biomechanical Engineering , 128(5), 742-750. PubMed ID: 16995761