Myocardial Material Parameter Estimation—A Comparative Study for Simple Shear

Abstract

The study of ventricular mechanics—analyzing the distribution of strain and stress in myocardium throughout the cardiac cycle—is crucially dependent on the accuracy of the constitutive law chosen to represent the highly nonlinear and anisotropic properties of passive cardiac muscle. A number of such laws have been proposed and fitted to experimental measurements of stress-strain behavior. Here we examine five of these laws and compare them on the basis of (i) “goodness of fit:” How well they fit a set of six shear deformation tests, (ii) “determinability:” How well determined the objective function is at the optimal parameter fit, and (iii) “variability:” How well determined the material parameters are over the range of experiments. These criteria are utilized to discuss the advantages and disadvantages of the constitutive laws.