Document Detail

Increased left ventricular twist, untwisting rates, and suction maintain global diastolic function during passive heat stress in humans.
MedLine Citation:
PMID:  20061540     Owner:  NLM     Status:  MEDLINE    
Left ventricular (LV) systolic function increases with passive heat stress (HS); however, less is known about diastolic function. Eight healthy subjects (24.0 +/- 2.0 yr of age) underwent whole body passive heating approximately 1 degrees C above baseline (BL). Cardiac magnetic resonance imaging was used to measure biventricular volumes, function, filling velocities, volumetric flow rates, and LV twist and strain at BL and after 45 min of HS. Passive heating reduced left atrial volume (-17.6 +/- 11.7 ml, P < 0.05), right and LV end-diastolic volumes (-22.7 +/- 11.0 and -25.7 +/- 24.9 ml, respectively; P < 0.05), and LV stroke volume (-6.7 +/- 6.8 ml, P < 0.05) from BL. LV ejection fraction (EF), end-systolic elastance, septal and lateral mitral annular systolic velocities, circumferential strain, and peak LV twist increased with HS (P < 0.05). Right ventricular stroke volume, EF, and systolic tissue velocities were unchanged with HS (P > 0.05). Early LV diastolic tissue and blood velocities and strain rates were maintained with HS, whereas untwisting rate increased significantly from 166.4 +/- 46.9 to 268.7 +/- 76.8 degrees /s (P < 0.05). The major novel finding of this study was that, secondary to an increase in peak LV twist and untwisting rate, early diastolic blood and tissue velocities and strain rates are maintained despite a reduction in filling pressure.
Michael D Nelson; Mark J Haykowsky; Stewart R Petersen; Darren S DeLorey; June Cheng-Baron; Richard B Thompson
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-01-08
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  298     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-02-25     Completed Date:  2010-04-02     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:  H930-7     Citation Subset:  IM    
Department of Physical Therapy, Univ. of Alberta, Edmonton, AB, Canada.
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MeSH Terms
Blood Flow Velocity / physiology
Body Temperature / physiology*
Diastole / physiology*
Heart Ventricles / pathology,  physiopathology*
Hot Temperature*
Magnetic Resonance Imaging
Stroke Volume / physiology
Grant Support
//Canadian Institutes of Health Research

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

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