Document Detail


Enhanced ventricular untwisting during exercise: a mechanistic manifestation of elastic recoil described by Doppler tissue imaging.
MedLine Citation:
PMID:  16717149     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: The cascade of events by which early diastolic left ventricular (LV) filling increases with exercise is not fully elucidated. Doppler tissue imaging (DTI) can detect myocardial motion, including torsion, whereas color M-mode Doppler (CMM) can quantify LV intraventricular pressure gradients (IVPGs). METHODS AND RESULTS: Twenty healthy volunteers underwent echocardiographic examination with DTI at rest and during submaximal supine bicycle exercise. We assessed LV long-/short-axis function, torsion, volume, inflow dynamics, and early diastolic IVPG derived from CMM data. LV torsion and untwisting velocity increased with exercise (torsion, 11+/-4 degrees to 24+/-8 degrees ; untwisting velocity, -2.0+/-0.7 to -5.6+/-2.3 rad/s) that was associated with an increase in IVPG (1.4+/-0.5 to 3.7+/-1.2 mm Hg). Untwisting in normal subjects occurred during isovolumic relaxation and early filling, significantly before long-axis lengthening or radial expansion. The clinical feasibility of this method was tested in 7 patients with hypertrophic cardiomyopathy (HCM); torsion was higher at rest but did not increase with exercise (16+/-4 degrees to 14+/-6 degrees), whereas untwisting was delayed and unenhanced (-1.6+/-0.8 to -2.3+/-1.2 rad/s). In concert, IVPG was similar at rest (1.2+/-0.3 mm Hg), but the exercise response was blunted (1.6+/-0.8 mm Hg). In normal subjects and HCM patients, there was a similar linear relation between IVPG and untwisting rate, with an overall correlation coefficient of r=0.75 (P<0.0001). CONCLUSIONS: LV untwisting appears to be linked temporally with early diastolic base-to-apex pressure gradients, enhanced by exercise, which may assist efficient LV filling, an effect that appears blunted in HCM. Thus, LV torsion and subsequent rapid untwisting appear to be manifestations of elastic recoil, critically linking systolic contraction to diastolic filling.
Authors:
Yuichi Notomi; Maureen G Martin-Miklovic; Stephanie J Oryszak; Takahiro Shiota; Dimitri Deserranno; Zoran B Popovic; Mario J Garcia; Neil L Greenberg; James D Thomas
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2006-05-22
Journal Detail:
Title:  Circulation     Volume:  113     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2006 May 
Date Detail:
Created Date:  2006-05-31     Completed Date:  2006-06-20     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2524-33     Citation Subset:  AIM; IM    
Affiliation:
Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Biomechanics
Cardiomyopathy, Hypertrophic / ultrasonography
Echocardiography, Doppler*
Exercise / physiology*
Female
Humans
Male
Motion
Myocardial Contraction
Ventricular Function, Left / physiology*
Grant Support
ID/Acronym/Agency:
AG17479-02/AG/NIA NIH HHS; M01 RR-018390/RR/NCRR NIH HHS
Comments/Corrections
Comment In:
Circulation. 2006 May 30;113(21):2477-9   [PMID:  16735687 ]

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


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