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Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance
To date, the mechanical loads imposed on isolated cardiac muscle tissue in vitro have been oversimplified. Researchers typically applied loads that are time‐invariant, resulting in either isometric and auxotonic contractions, or flat‐topped (isotonic shortening) work‐loops. These contraction types d...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6739510/ https://www.ncbi.nlm.nih.gov/pubmed/31512409 http://dx.doi.org/10.14814/phy2.14184 |
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author | Garrett, Amy S. Pham, Toan Loiselle, Denis Han, June‐Chiew Taberner, Andrew |
author_facet | Garrett, Amy S. Pham, Toan Loiselle, Denis Han, June‐Chiew Taberner, Andrew |
author_sort | Garrett, Amy S. |
collection | PubMed |
description | To date, the mechanical loads imposed on isolated cardiac muscle tissue in vitro have been oversimplified. Researchers typically applied loads that are time‐invariant, resulting in either isometric and auxotonic contractions, or flat‐topped (isotonic shortening) work‐loops. These contraction types do not fully capture the dynamic response of contracting tissues adapting to a variable load, such as is experienced by ventricular tissue in vivo. In this study, we have successfully developed a loading system that presents a model‐based, time‐varying, continuously updated, load to cardiac tissue preparations. We combined a Windkessel model of vascular fluid impedance together with Laplace's Law and encoded it in a real‐time hardware‐based force‐length control system. Experiments were carried out on isolated rat left ventricular trabeculae; we directly compare the work‐loops arising from this protocol with those of a typical simplified isotonic shortening work‐loop system. We found that, under body conditions, cardiac trabeculae achieved greater mechanical work output against our new loading system, than with the simplified isotonic work‐loop protocol. We further tested whether loading the tissue with a mechanical impedance defined by “diseased” Windkessel model parameters had an effect on the performance of healthy trabeculae. We found that trabecula shortening decreased when applying the set of Windkessel parameters describing the hypertensive condition, and increased in the hypotensive state. Our implementation of a real‐time model of arterial characteristics provides an improved, physiologically derived, instantly calculated load for use in studying isolated cardiac muscle, and is readily applicable to study various disease conditions. |
format | Online Article Text |
id | pubmed-6739510 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-67395102019-09-14 Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance Garrett, Amy S. Pham, Toan Loiselle, Denis Han, June‐Chiew Taberner, Andrew Physiol Rep Original Research To date, the mechanical loads imposed on isolated cardiac muscle tissue in vitro have been oversimplified. Researchers typically applied loads that are time‐invariant, resulting in either isometric and auxotonic contractions, or flat‐topped (isotonic shortening) work‐loops. These contraction types do not fully capture the dynamic response of contracting tissues adapting to a variable load, such as is experienced by ventricular tissue in vivo. In this study, we have successfully developed a loading system that presents a model‐based, time‐varying, continuously updated, load to cardiac tissue preparations. We combined a Windkessel model of vascular fluid impedance together with Laplace's Law and encoded it in a real‐time hardware‐based force‐length control system. Experiments were carried out on isolated rat left ventricular trabeculae; we directly compare the work‐loops arising from this protocol with those of a typical simplified isotonic shortening work‐loop system. We found that, under body conditions, cardiac trabeculae achieved greater mechanical work output against our new loading system, than with the simplified isotonic work‐loop protocol. We further tested whether loading the tissue with a mechanical impedance defined by “diseased” Windkessel model parameters had an effect on the performance of healthy trabeculae. We found that trabecula shortening decreased when applying the set of Windkessel parameters describing the hypertensive condition, and increased in the hypotensive state. Our implementation of a real‐time model of arterial characteristics provides an improved, physiologically derived, instantly calculated load for use in studying isolated cardiac muscle, and is readily applicable to study various disease conditions. John Wiley and Sons Inc. 2019-09-11 /pmc/articles/PMC6739510/ /pubmed/31512409 http://dx.doi.org/10.14814/phy2.14184 Text en © 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Research Garrett, Amy S. Pham, Toan Loiselle, Denis Han, June‐Chiew Taberner, Andrew Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance |
title | Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance |
title_full | Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance |
title_fullStr | Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance |
title_full_unstemmed | Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance |
title_short | Mechanical loading of isolated cardiac muscle with a real‐time computed Windkessel model of the vasculature impedance |
title_sort | mechanical loading of isolated cardiac muscle with a real‐time computed windkessel model of the vasculature impedance |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6739510/ https://www.ncbi.nlm.nih.gov/pubmed/31512409 http://dx.doi.org/10.14814/phy2.14184 |
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