Document Detail


Wave intensity analysis of left atrial mechanics and energetics in anesthetized dogs.
MedLine Citation:
PMID:  17114242     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The left atrium (LA) acts as a booster pump during late diastole, generating the Doppler transmitral A wave and contributing incrementally to left ventricular (LV) filling. However, after volume loading and in certain disease states, LA contraction fills the LV less effectively, and retrograde flow (i.e., the Doppler Ar wave) into the pulmonary veins increases. The purpose of this study was to provide an energetic analysis of LA contraction to clarify the mechanisms responsible for changes in forward and backward flow. Wave intensity analysis was performed at the mitral valve and a pulmonary vein orifice. As operative LV stiffness increased with progressive volume loading, the reflection coefficient (i.e., energy of reflected wave/energy of incident wave) also increased. This reflected wave decelerated the forward movement of blood through the mitral valve and was transmitted through the LA, accelerating retrograde blood flow in the pulmonary veins. Although total LA work increased with volume loading, the forward hydraulic work decreased and backward hydraulic work increased. Thus wave reflection due to increased LV stiffness accounts for the decrease in the A wave and the increase in the Ar wave measured by Doppler.
Authors:
Tracy N Hobson; Jacqueline A Flewitt; Israel Belenkie; John V Tyberg
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-11-17
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  292     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-03-06     Completed Date:  2007-04-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1533-40     Citation Subset:  IM    
Affiliation:
Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Health Sciences Centre, Univ of Calgary, Calgary, Alberta, Canada.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Atrial Function, Left / physiology*
Blood Pressure
Carotid Arteries / physiology
Dogs
Heart Atria / ultrasonography
Myocardial Contraction
Pulmonary Veins / physiology
Ultrasonography, Doppler

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


Previous Document:  Magnesium attenuates isoproterenol-induced acute cardiac dysfunction and beta-adrenergic desensitiza...
Next Document:  High dietary salt reduces the contribution of 20-HETE to arteriolar oxygen responsiveness in skeleta...