Document Detail


Vagal nerve stimulation reduces anterior mitral valve leaflet stiffness in the beating ovine heart.
MedLine Citation:
PMID:  22703898     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
AIM: The functional significance of the autonomic nerves in the anterior mitral valve leaflet (AML) is unknown. We tested the hypothesis that remote stimulation of the vagus nerve (VNS) reduces AML stiffness in the beating heart.
METHODS: Forty-eight radiopaque-markers were implanted into eleven ovine hearts to delineate left ventricular and mitral anatomy, including an AML array. The anesthetized animals were then taken to the catheterization laboratory and 4-D marker coordinates obtained from biplane videofluoroscopy before and after VNS. Circumferential (E(circ)) and radial (E(rad)) stiffness values for three separate AML regions, Annulus, Belly and Edge, were obtained from inverse finite element analysis of AML displacements in response to trans-leaflet pressure changes during isovolumic contraction (IVC) and isovolumic relaxation (IVR).
RESULTS: VNS reduced heart rate: 94±9 vs. 82±10min(-1), (mean±SD, p<0.001). Circumferential AML stiffness was significantly reduced in all three regions during IVC and IVR (all p<0.05). Radial AML stiffness was reduced from control in the annular and belly regions at both IVC and IVR (P<0.05), while the reduction did not reach significance at the AML edge.
CONCLUSION: These observations suggest that one potential functional role for the parasympathetic nerves in the AML is to alter leaflet stiffness. Neural control of the contractile tissue in the AML could be part of a central control system capable of altering valve stiffness to adapt to changing hemodynamic demands.
Authors:
Julia C Swanson; Gaurav Krishnamurthy; Akinobu Itoh; John-Peder Escobar Kvitting; Wolfgang Bothe; D Craig Miller; Neil B Ingels
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-06-15
Journal Detail:
Title:  Journal of biomechanics     Volume:  45     ISSN:  1873-2380     ISO Abbreviation:  J Biomech     Publication Date:  2012 Jul 
Date Detail:
Created Date:  2012-07-09     Completed Date:  2012-11-16     Revised Date:  2013-07-31    
Medline Journal Info:
Nlm Unique ID:  0157375     Medline TA:  J Biomech     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2007-13     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Elsevier Ltd. All rights reserved.
Affiliation:
Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, CA, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Computer Simulation
Elastic Modulus / physiology
Electric Stimulation / methods*
Mitral Valve / innervation*,  physiology*
Models, Cardiovascular*
Parasympathetic Nervous System / physiology*
Sheep
Vagus Nerve / physiology*
Grant Support
ID/Acronym/Agency:
R01 HL-29589/HL/NHLBI NIH HHS; R01 HL-67025/HL/NHLBI NIH HHS; R01 HL067025/HL/NHLBI NIH HHS
Comments/Corrections

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