Compressibility and Anisotropy of the Ventricular Myocardium: Experimental Analysis and Microstructural Modeling

Eoin McEvoy, Gerhard A Holzapfel, Patrick McGarry

Research output: Contribution to journalArticleResearchpeer-review

Abstract

While the anisotropic behavior of the complex composite myocardial tissue has been well characterized in recent years, the compressibility of the tissue has not been rigorously investigated to date. In the first part of this study, we present experimental evidence that passive-excised porcine myocardium exhibits volume change. Under tensile loading of a cylindrical specimen, a volume change of 4.1±1.95% is observed at a peak stretch of 1.3. Confined compression experiments also demonstrate significant volume change in the tissue (loading applied up to a volumetric strain of 10%). In order to simulate the multiaxial passive behavior of the myocardium, a nonlinear volumetric hyperelastic component is combined with the well-established Holzapfel-Ogden anisotropic hyperelastic component for myocardium fibers. This framework is shown to describe the experimentally observed behavior of porcine and human tissues under shear and biaxial loading conditions. In the second part of the study, a representative volumetric element (RVE) of myocardium tissue is constructed to parse the contribution of the tissue vasculature to observed volume change under confined compression loading. Simulations of the myocardium microstructure suggest that the vasculature cannot fully account for the experimentally measured volume change. Additionally, the RVE is subjected to six modes of shear loading to investigate the influence of microscale fiber alignment and dispersion on tissue-scale mechanical behavior.

Original languageEnglish
Article number081004
JournalJournal of biomechanical engineering
Volume140
Issue number8
DOIs
Publication statusPublished - 1 Aug 2018

Fingerprint

Anisotropy
Compressibility
Myocardium
Tissue
Swine
Fibers
Compaction
Microstructure
Composite materials

Cite this

Compressibility and Anisotropy of the Ventricular Myocardium : Experimental Analysis and Microstructural Modeling. / McEvoy, Eoin; Holzapfel, Gerhard A; McGarry, Patrick.

In: Journal of biomechanical engineering, Vol. 140, No. 8, 081004 , 01.08.2018.

Research output: Contribution to journalArticleResearchpeer-review

@article{0d1a4800521340bfbab895581e093e00,
title = "Compressibility and Anisotropy of the Ventricular Myocardium: Experimental Analysis and Microstructural Modeling",
abstract = "While the anisotropic behavior of the complex composite myocardial tissue has been well characterized in recent years, the compressibility of the tissue has not been rigorously investigated to date. In the first part of this study, we present experimental evidence that passive-excised porcine myocardium exhibits volume change. Under tensile loading of a cylindrical specimen, a volume change of 4.1±1.95{\%} is observed at a peak stretch of 1.3. Confined compression experiments also demonstrate significant volume change in the tissue (loading applied up to a volumetric strain of 10{\%}). In order to simulate the multiaxial passive behavior of the myocardium, a nonlinear volumetric hyperelastic component is combined with the well-established Holzapfel-Ogden anisotropic hyperelastic component for myocardium fibers. This framework is shown to describe the experimentally observed behavior of porcine and human tissues under shear and biaxial loading conditions. In the second part of the study, a representative volumetric element (RVE) of myocardium tissue is constructed to parse the contribution of the tissue vasculature to observed volume change under confined compression loading. Simulations of the myocardium microstructure suggest that the vasculature cannot fully account for the experimentally measured volume change. Additionally, the RVE is subjected to six modes of shear loading to investigate the influence of microscale fiber alignment and dispersion on tissue-scale mechanical behavior.",
author = "Eoin McEvoy and Holzapfel, {Gerhard A} and Patrick McGarry",
year = "2018",
month = "8",
day = "1",
doi = "10.1115/1.4039947",
language = "English",
volume = "140",
journal = "Journal of biomechanical engineering",
issn = "0148-0731",
publisher = "American Society of Mechanical Engineers(ASME)",
number = "8",

}

TY - JOUR

T1 - Compressibility and Anisotropy of the Ventricular Myocardium

T2 - Experimental Analysis and Microstructural Modeling

AU - McEvoy, Eoin

AU - Holzapfel, Gerhard A

AU - McGarry, Patrick

PY - 2018/8/1

Y1 - 2018/8/1

N2 - While the anisotropic behavior of the complex composite myocardial tissue has been well characterized in recent years, the compressibility of the tissue has not been rigorously investigated to date. In the first part of this study, we present experimental evidence that passive-excised porcine myocardium exhibits volume change. Under tensile loading of a cylindrical specimen, a volume change of 4.1±1.95% is observed at a peak stretch of 1.3. Confined compression experiments also demonstrate significant volume change in the tissue (loading applied up to a volumetric strain of 10%). In order to simulate the multiaxial passive behavior of the myocardium, a nonlinear volumetric hyperelastic component is combined with the well-established Holzapfel-Ogden anisotropic hyperelastic component for myocardium fibers. This framework is shown to describe the experimentally observed behavior of porcine and human tissues under shear and biaxial loading conditions. In the second part of the study, a representative volumetric element (RVE) of myocardium tissue is constructed to parse the contribution of the tissue vasculature to observed volume change under confined compression loading. Simulations of the myocardium microstructure suggest that the vasculature cannot fully account for the experimentally measured volume change. Additionally, the RVE is subjected to six modes of shear loading to investigate the influence of microscale fiber alignment and dispersion on tissue-scale mechanical behavior.

AB - While the anisotropic behavior of the complex composite myocardial tissue has been well characterized in recent years, the compressibility of the tissue has not been rigorously investigated to date. In the first part of this study, we present experimental evidence that passive-excised porcine myocardium exhibits volume change. Under tensile loading of a cylindrical specimen, a volume change of 4.1±1.95% is observed at a peak stretch of 1.3. Confined compression experiments also demonstrate significant volume change in the tissue (loading applied up to a volumetric strain of 10%). In order to simulate the multiaxial passive behavior of the myocardium, a nonlinear volumetric hyperelastic component is combined with the well-established Holzapfel-Ogden anisotropic hyperelastic component for myocardium fibers. This framework is shown to describe the experimentally observed behavior of porcine and human tissues under shear and biaxial loading conditions. In the second part of the study, a representative volumetric element (RVE) of myocardium tissue is constructed to parse the contribution of the tissue vasculature to observed volume change under confined compression loading. Simulations of the myocardium microstructure suggest that the vasculature cannot fully account for the experimentally measured volume change. Additionally, the RVE is subjected to six modes of shear loading to investigate the influence of microscale fiber alignment and dispersion on tissue-scale mechanical behavior.

U2 - 10.1115/1.4039947

DO - 10.1115/1.4039947

M3 - Article

VL - 140

JO - Journal of biomechanical engineering

JF - Journal of biomechanical engineering

SN - 0148-0731

IS - 8

M1 - 081004

ER -