Document Detail


Alterations in left ventricular torsion in tachycardia-induced dilated cardiomyopathy.
MedLine Citation:
PMID:  12091807     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Left ventricular torsion reduces transmural systolic gradients of fiber strain, and torsional recoil in early diastole is thought to enhance left ventricular filling. Left ventricular remodeling in dilated cardiomyopathy may result in changes in torsion dynamics, but these effects are not yet characterized. Tachycardia-induced cardiomyopathy is accompanied by systolic and diastolic heart failure and left ventricular remodeling. We hypothesized that cardiomyopathy would alter systolic and diastolic left ventricular torsion mechanics, and this hypothesis was tested by studying sheep before and after the development of tachycardia-induced cardiomyopathy. METHODS: Implanted miniature radiopaque markers were used in 8 sheep to measure left ventricular geometry and function, maximal torsional deformation, and early diastolic recoil before and after rapid ventricular pacing was used to create tachycardia-induced cardiomyopathy. RESULTS: All animals had significant heart failure with ventricular dilatation and remodeling. With tachycardia-induced cardiomyopathy, maximum torsion relative to control conditions decreased (1.69 degrees +/- 0.61 degrees vs 4.25 degrees +/- 2.33 degrees ), and early diastolic recoil was completely abolished (0.53 degrees +/- 1.19 degrees vs -1.17 degrees +/- 0.94 degrees ). CONCLUSIONS: Cardiomyopathy is accompanied by decreased and delayed systolic left ventricular torsional deformation and loss of early diastolic recoil, which may contribute to left ventricular dysfunction by increasing systolic transmural strain gradients and impairing diastolic filling. Analysis of left ventricular torsion with radiofrequency-tagging magnetic resonance imaging should be explored to elucidate the role of torsion in patients with cardiomyopathy.
Authors:
Frederick A Tibayan; David T M Lai; Tomasz A Timek; Paul Dagum; David Liang; George T Daughters; Neil B Ingels; D Craig Miller
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  124     ISSN:  0022-5223     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-07-01     Completed Date:  2002-08-06     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0376343     Medline TA:  J Thorac Cardiovasc Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  43-9     Citation Subset:  AIM; IM    
Affiliation:
Department of Cardiovascular and Thoracic Surgery, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA 94305-5247, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cardiac Pacing, Artificial
Cardiomyopathy, Dilated / etiology,  physiopathology*
Hemodynamics / physiology
Myocardial Contraction / physiology
Sheep
Tachycardia / physiopathology
Torsion Abnormality
Ventricular Dysfunction, Left / physiopathology*
Ventricular Remodeling / physiology
Grant Support
ID/Acronym/Agency:
HL-09569/HL/NHLBI NIH HHS; HL-10452/HL/NHLBI NIH HHS; HL-29589/HL/NHLBI NIH HHS; HL-67025/HL/NHLBI NIH HHS; HL-67563/HL/NHLBI NIH HHS

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


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