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Passive and active ventricular elastances of the left ventricle
BACKGROUND: Description of the heart as a pump has been dominated by models based on elastance and compliance. Here, we are presenting a somewhat new concept of time-varying passive and active elastance. The mathematical basis of time-varying elastance of the ventricle is presented. We have defined...
Autores principales: | , , , |
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Formato: | Texto |
Lenguaje: | English |
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BioMed Central
2005
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC549522/ https://www.ncbi.nlm.nih.gov/pubmed/15707494 http://dx.doi.org/10.1186/1475-925X-4-10 |
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author | Zhong, Liang Ghista, Dhanjoo N Ng, Eddie YK Lim, Soo T |
author_facet | Zhong, Liang Ghista, Dhanjoo N Ng, Eddie YK Lim, Soo T |
author_sort | Zhong, Liang |
collection | PubMed |
description | BACKGROUND: Description of the heart as a pump has been dominated by models based on elastance and compliance. Here, we are presenting a somewhat new concept of time-varying passive and active elastance. The mathematical basis of time-varying elastance of the ventricle is presented. We have defined elastance in terms of the relationship between ventricular pressure and volume, as: dP = EdV + VdE, where E includes passive (E(p)) and active (E(a)) elastance. By incorporating this concept in left ventricular (LV) models to simulate filling and systolic phases, we have obtained the time-varying expression for E(a )and the LV-volume dependent expression for E(p). METHODS AND RESULTS: Using the patient's catheterization-ventriculogram data, the values of passive and active elastance are computed. E(a )is expressed as: [Image: see text]; E(p)is represented as: [Image: see text]. E(a )is deemed to represent a measure of LV contractility. Hence, Peak dP/dt and ejection fraction (EF) are computed from the monitored data and used as the traditional measures of LV contractility. When our computed peak active elastance (E(a,max)) is compared against these traditional indices by linear regression, a high degree of correlation is obtained. As regards E(p), it constitutes a volume-dependent stiffness property of the LV, and is deemed to represent resistance-to-filling. CONCLUSIONS: Passive and active ventricular elastance formulae can be evaluated from a single-beat P-V data by means of a simple-to-apply LV model. The active elastance (E(a)) can be used to characterize the ventricle's contractile state, while passive elastance (E(p)) can represent a measure of resistance-to-filling. |
format | Text |
id | pubmed-549522 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2005 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-5495222005-02-25 Passive and active ventricular elastances of the left ventricle Zhong, Liang Ghista, Dhanjoo N Ng, Eddie YK Lim, Soo T Biomed Eng Online Research BACKGROUND: Description of the heart as a pump has been dominated by models based on elastance and compliance. Here, we are presenting a somewhat new concept of time-varying passive and active elastance. The mathematical basis of time-varying elastance of the ventricle is presented. We have defined elastance in terms of the relationship between ventricular pressure and volume, as: dP = EdV + VdE, where E includes passive (E(p)) and active (E(a)) elastance. By incorporating this concept in left ventricular (LV) models to simulate filling and systolic phases, we have obtained the time-varying expression for E(a )and the LV-volume dependent expression for E(p). METHODS AND RESULTS: Using the patient's catheterization-ventriculogram data, the values of passive and active elastance are computed. E(a )is expressed as: [Image: see text]; E(p)is represented as: [Image: see text]. E(a )is deemed to represent a measure of LV contractility. Hence, Peak dP/dt and ejection fraction (EF) are computed from the monitored data and used as the traditional measures of LV contractility. When our computed peak active elastance (E(a,max)) is compared against these traditional indices by linear regression, a high degree of correlation is obtained. As regards E(p), it constitutes a volume-dependent stiffness property of the LV, and is deemed to represent resistance-to-filling. CONCLUSIONS: Passive and active ventricular elastance formulae can be evaluated from a single-beat P-V data by means of a simple-to-apply LV model. The active elastance (E(a)) can be used to characterize the ventricle's contractile state, while passive elastance (E(p)) can represent a measure of resistance-to-filling. BioMed Central 2005-02-11 /pmc/articles/PMC549522/ /pubmed/15707494 http://dx.doi.org/10.1186/1475-925X-4-10 Text en Copyright © 2005 Zhong et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Zhong, Liang Ghista, Dhanjoo N Ng, Eddie YK Lim, Soo T Passive and active ventricular elastances of the left ventricle |
title | Passive and active ventricular elastances of the left ventricle |
title_full | Passive and active ventricular elastances of the left ventricle |
title_fullStr | Passive and active ventricular elastances of the left ventricle |
title_full_unstemmed | Passive and active ventricular elastances of the left ventricle |
title_short | Passive and active ventricular elastances of the left ventricle |
title_sort | passive and active ventricular elastances of the left ventricle |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC549522/ https://www.ncbi.nlm.nih.gov/pubmed/15707494 http://dx.doi.org/10.1186/1475-925X-4-10 |
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