Computational Modelling of Cardiac Trabecula Mechanics

Abstract

Cardiac trabeculae are thin strips of muscle within the ventricles that can be readily excised and used to investigate contractile mechanics of cardiac muscle. Recently, the Auckland Bioengineering Institute has developed a novel cardiac myometer that simultaneously measures force, length and shape of actively contracting isolated cardiac trabeculae. Here we have developed a muscle-specific computational model based on optical coherence tomography geometric surface data that replicates passive mechanics of trabecula. We hypothesised that the muscle's surface geometry data, in addition to force-length data, would improve the fit between the model simulated mechanics and the experimental data. The trabecula model was optimised using two different objective functions (muscle length or shape) driven by a pressure boundary condition. For both objective functions, there was a region of optimal parameters the optimiser tended towards but, due to the coupling between parameters, the ability to find the true optimal parameters was hindered. Due to the limitations of the data, we found that the addition of surface data did not improve parameter estimation and that using only the force-length data provided sufficient information to produce an optimal fit.