Document Detail


Elucidation of spatially distinct compensatory mechanisms in diastole: radial compensation for impaired longitudinal filling in left ventricular hypertrophy.
MedLine Citation:
PMID:  18032579     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cardiac output maintenance is so fundamental that, when regional systolic function is impaired, as during ischemia, nonischemic segments compensate by becoming hypercontractile. By analogy, diastolic compensatory mechanisms that maintain filling volume must exist but remain to be fully elucidated. Viewing filling in spatially distinct (longitudinal, radial) mechanistic terms facilitates elucidation of diastolic compensatory mechanisms. Because impairment of longitudinal (long axis) diastolic function (DF) in left ventricular hypertrophy (LVH) is established, we hypothesized that to maintain filling volume, radial (short-axis) filling function would compensate. In 20 normal left ventricular ejection fraction (LVEF) subjects (10 with LVH, 10 without LVH), we analyzed longitudinal function via Doppler tissue imaging of mitral annular motion and radial function as change in short-axis endocardial dimension via M-mode. The spatial (long axis, short axis) endocardial LV dimensions and their changes allowed assignment of E-wave filling volume into (cylindrical geometry-based) longitudinal and radial components. Despite indistinguishable (P = 0.70) E-wave velocity-time integrals (E-wave filling volume surrogate), systolic stroke volumes, and end-diastolic volumes in the LVH and control groups, longitudinal volume in absolute terms and the percent of E-wave volume accommodated longitudinally were reduced in the LVH group (P < 0.05 and P < 0.01, respectively), whereas the percent of E-wave volume accommodated radially was enhanced (P < 0.01). We conclude that, in normal LVEF (decreased longitudinal volume accommodation) LVH subjects vs. controls, spatially distinct compensatory mechanisms in diastole manifest as increased radial volume accommodation per unit of E-wave filling volume. Assessment of spatially distinct diastolic compensatory mechanisms in other pathophysiological subsets is warranted.
Authors:
Matt M Riordan; Sándor J Kovács
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2007-11-21
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  104     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2008 Feb 
Date Detail:
Created Date:  2008-02-11     Completed Date:  2008-04-04     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  513-20     Citation Subset:  IM    
Affiliation:
Department of Biomedical Engineering, School of Engineering and Applied Science, Washington University School of Medicine, St. Louis, MO 63110, USA.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological*
Adult
Aged
Blood Pressure
Case-Control Studies
Diastole*
Echocardiography, Doppler
Endocardium / physiopathology,  ultrasonography
Heart Rate
Hemodynamics*
Humans
Hypertrophy, Left Ventricular / physiopathology*,  ultrasonography
Middle Aged
Mitral Valve / physiopathology,  ultrasonography
Models, Cardiovascular
Stroke Volume
Time Factors
Ventricular Function, Left*
Grant Support
ID/Acronym/Agency:
HL-04023/HL/NHLBI NIH HHS; HL-54179/HL/NHLBI NIH HHS

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


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