Document Detail

Contribution of mitral annular dynamics to LV diastolic filling with alteration in preload and inotropic state.
MedLine Citation:
PMID:  17496217     Owner:  NLM     Status:  MEDLINE    
Mitral annular (MA) excursion during diastole encompasses a volume that is part of total left ventricular (LV) filling volume (LVFV). Altered excursion or area variation of the MA due to changes in preload or inotropic state could affect LV filling. We hypothesized that changes in LV preload and inotropic state would not alter the contribution of MA dynamics to LVFV. Six sheep underwent marker implantation in the LV wall and around the MA. After 7-10 days, biplane fluoroscopy was used to obtain three-dimensional marker dynamics from sedated, closed-chest animals during control conditions, inotropic augmentation with calcium (Ca), preload reduction with nitroprusside (N), and vena caval occlusion (VCO). The contribution of MA dynamics to total LVFV was assessed using volume estimates based on multiple tetrahedra defined by the three-dimensional marker positions. Neither the absolute nor the relative contribution of MA dynamics to LVFV changed with Ca or N, although MA area decreased (Ca, P < 0.01; and N, P < 0.05) and excursion increased (Ca, P < 0.01). During VCO, the absolute contribution of MA dynamics to LVFV decreased (P < 0.001), based on a reduction in both area (P < 0.001) and excursion (P < 0.01), but the relative contribution to LVFV increased from 18 +/- 4 to 45 +/- 13% (P < 0.001). Thus MA dynamics contribute substantially to LV diastolic filling. Although MA excursion and mean area change with moderate preload reduction and inotropic augmentation, the contribution of MA dynamics to total LVFV is constant with sizeable magnitude. With marked preload reduction (VCO), the contribution of MA dynamics to LVFV becomes even more important.
C Carlhäll; K Kindberg; L Wigström; G T Daughters; D C Miller; M Karlsson; N 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:  2007-05-11
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  293     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-09-06     Completed Date:  2007-10-19     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1473-9     Citation Subset:  IM    
Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, USA.
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MeSH Terms
Calcium / pharmacology
Mitral Valve / drug effects,  physiology*
Myocardial Contraction / drug effects,  physiology*
Nitroprusside / pharmacology
Vasodilator Agents / pharmacology
Ventricular Function, Left / drug effects,  physiology*
Ventricular Pressure
Grant Support
Reg. No./Substance:
0/Vasodilator Agents; 15078-28-1/Nitroprusside; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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