An orthotropic electro-viscoelastic model for the heart with stress-assisted diffusion

Adrienne Propp, Alessio Gizzi, Francesc Levrero-Florencio, Ricardo Ruiz-Baier

Research output: Contribution to journalArticleResearchpeer-review

Abstract

We propose and analyse the properties of a new class of models for the electromechanics of cardiac tissue. The set of governing equations consists of nonlinear elasticity using a viscoelastic and orthotropic exponential constitutive law, for both active stress and active strain formulations of active mechanics, coupled with a four-variable phenomenological model for human cardiac cell electrophysiology, which produces an accurate description of the action potential. The conductivities in the model of electric propagation are modified according to stress, inducing an additional degree of nonlinearity and anisotropy in the coupling mechanisms, and the activation model assumes a simplified stretch–calcium interaction generating active tension or active strain. The influence of the new terms in the electromechanical model is evaluated through a sensitivity analysis, and we provide numerical validation through a set of computational tests using a novel mixed-primal finite element scheme.

Original languageEnglish
Pages (from-to)633-659
Number of pages27
JournalBiomechanics and Modeling in Mechanobiology
Volume19
DOIs
Publication statusPublished - Apr 2020
Externally publishedYes

Keywords

  • Cardiac electromechanics
  • Kirchhoff stress formulation
  • Mixed-primal finite element method
  • Orthotropic nonlinear elasticity
  • Stress-assisted diffusion
  • Viscoelastic response

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