Passive and active ventricular elastances of the left ventricle
<p>Abstract</p> <p>Background</p> <p>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 el...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2005-02-01
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| Series: | BioMedical Engineering OnLine |
| Online Access: | http://www.biomedical-engineering-online.com/content/4/1/10 |
| _version_ | 1828922717733126144 |
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| author | Ng Eddie YK Ghista Dhanjoo N Zhong Liang Lim Soo T |
| author_facet | Ng Eddie YK Ghista Dhanjoo N Zhong Liang Lim Soo T |
| author_sort | Ng Eddie YK |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>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: <it>dP </it>= <it>EdV </it>+ <it>VdE</it>, where E includes passive (E<sub>p</sub>) and active (E<sub>a</sub>) 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<sub>a </sub>and the LV-volume dependent expression for E<sub>p</sub>.</p> <p>Methods and Results</p> <p>Using the patient's catheterization-ventriculogram data, the values of passive and active elastance are computed. E<sub>a </sub>is expressed as: <graphic file="1475-925X-4-10-i1.gif"/>; E<sub>p</sub>is represented as: <graphic file="1475-925X-4-10-i2.gif"/>. E<sub>a </sub>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<sub>a,max</sub>) is compared against these traditional indices by linear regression, a high degree of correlation is obtained. As regards E<sub>p</sub>, it constitutes a volume-dependent stiffness property of the LV, and is deemed to represent resistance-to-filling.</p> <p>Conclusions</p> <p>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<sub>a</sub>) can be used to characterize the ventricle's contractile state, while passive elastance (E<sub>p</sub>) can represent a measure of resistance-to-filling.</p> |
| first_indexed | 2024-12-13T22:25:36Z |
| format | Article |
| id | doaj.art-5ac882b396374c8198cde1662d47c6d0 |
| institution | Directory Open Access Journal |
| issn | 1475-925X |
| language | English |
| last_indexed | 2024-12-13T22:25:36Z |
| publishDate | 2005-02-01 |
| publisher | BMC |
| record_format | Article |
| series | BioMedical Engineering OnLine |
| spelling | doaj.art-5ac882b396374c8198cde1662d47c6d02022-12-21T23:29:13ZengBMCBioMedical Engineering OnLine1475-925X2005-02-01411010.1186/1475-925X-4-10Passive and active ventricular elastances of the left ventricleNg Eddie YKGhista Dhanjoo NZhong LiangLim Soo T<p>Abstract</p> <p>Background</p> <p>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: <it>dP </it>= <it>EdV </it>+ <it>VdE</it>, where E includes passive (E<sub>p</sub>) and active (E<sub>a</sub>) 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<sub>a </sub>and the LV-volume dependent expression for E<sub>p</sub>.</p> <p>Methods and Results</p> <p>Using the patient's catheterization-ventriculogram data, the values of passive and active elastance are computed. E<sub>a </sub>is expressed as: <graphic file="1475-925X-4-10-i1.gif"/>; E<sub>p</sub>is represented as: <graphic file="1475-925X-4-10-i2.gif"/>. E<sub>a </sub>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<sub>a,max</sub>) is compared against these traditional indices by linear regression, a high degree of correlation is obtained. As regards E<sub>p</sub>, it constitutes a volume-dependent stiffness property of the LV, and is deemed to represent resistance-to-filling.</p> <p>Conclusions</p> <p>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<sub>a</sub>) can be used to characterize the ventricle's contractile state, while passive elastance (E<sub>p</sub>) can represent a measure of resistance-to-filling.</p>http://www.biomedical-engineering-online.com/content/4/1/10 |
| spellingShingle | Ng Eddie YK Ghista Dhanjoo N Zhong Liang Lim Soo T Passive and active ventricular elastances of the left ventricle BioMedical Engineering OnLine |
| 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 |
| url | http://www.biomedical-engineering-online.com/content/4/1/10 |
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