| The relationship of normal and abnormal microstructural proliferation to the mitral valve closure sound. | |
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MedLine Citation:
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PMID: 15868796 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Many diseases that affect the mitral valve are accompanied by the proliferation or degradation of tissue microstructure. The early acoustic detection of these changes may lead to the better management of mitral valve disease. In this study, we examine the nonstationary acoustic effects of perturbing material parameters that characterize mitral valve tissue in terms of its microstructural components. Specifically, we examine the influence of the volume fraction, stiffness and splay of collagen fibers as well as the stiffness of the nonlinear matrix in which they are embedded. METHODS AND RESULTS: To model the transient vibrations of the mitral valve apparatus bathed in a blood medium, we have constructed a dynamic nonlinear fluid-coupled finite element model of the valve leaflets and chordae tendinae. The material behavior for the leaflets is based on an experimentally derived structural constitutive equation. The gross movement and small-scale acoustic vibrations of the valvular structures result from the application of physiologic pressure loads. Material changes that preserved the anisotropy of the valve leaflets were found to preserve valvular function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valvular function. These changes were manifest in the acoustic signatures of the valve closure sounds. Abnormally, stiffened valves closed more slowly and were accompanied by lower peak frequencies. CONCLUSION: The relationship between stiffness and frequency, though never documented in a native mitral valve, has been an axiom of heart sounds research. We find that the relationship is more subtle and that increases in stiffness may lead to either increases or decreases in peak frequency depending on their relationship to valvular function. |
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Authors:
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Daniel R Einstein; Karyn S Kunzelman; Per G Reinhall; Mark A Nicosia; Richard P Cochran |
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Publication Detail:
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Type: Comparative Study; Evaluation Studies; Journal Article; Validation Studies |
Journal Detail:
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Title: Journal of biomechanical engineering Volume: 127 ISSN: 0148-0731 ISO Abbreviation: J Biomech Eng Publication Date: 2005 Feb |
Date Detail:
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Created Date: 2005-05-04 Completed Date: 2005-07-19 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 7909584 Medline TA: J Biomech Eng Country: United States |
Other Details:
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Languages: eng Pagination: 134-47 Citation Subset: IM |
Affiliation:
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Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA. deinstein@chla.usc.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Computer Simulation Diagnosis, Computer-Assisted / methods* Heart Valve Diseases / diagnosis*, physiopathology* Mitral Valve / physiopathology* Models, Cardiovascular* Phonocardiography / methods* Reproducibility of Results Sensitivity and Specificity Sheep Sound Spectrography / methods* Statistics as Topic |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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