Document Detail


Is post-systolic shortening a reliable indicator of myocardial viability? An MR tagging and late-enhancement study.
MedLine Citation:
PMID:  16755830     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: In ischemic myocardium systolic strain is reduced and followed by a deformation after systole, the so-called post-systolic shortening. The presence of post systolic shortening is therefore considered a marker of viability even though its mechanism remains unclear. The hypothesis was tested whether post-systolic shortening might be a passive recoil phenomenon and therefore not uniquely associated with viability. METHODS: Five patients with a history of myocardial infarctions and fully transmural scars in late enhancement imaging and five age-matched healthy volunteers underwent a tagging study to analyze systolic and post-systolic deformation in transmurally infarcted and contra-lateral non-infarcted myocardium. From CSPAMM myocardial tagging data, mid-wall circumferential fiber shortening, radial displacement, and rotation parameters were semi-automatically extracted by harmonic phase (HARP). RESULTS: In transmurally infarcted myocardium, a post systolic shortening of 6.2 +/- 1.8% was present occurring in early diastole (time to maximum circumferential fiber shortening increased versus both, contralateral myocardium and corresponding sectors in healthy volunteers, p < 0.01). Maximum radial displacement was decreased in scar tissue (p < 0.001 versus contra-lateral), but time to maximum radial displacement did not differ. Rotation did not discriminate between infarcted and non-infarcted myocardium. CONCLUSIONS: The pure finding of post-systolic shortening is not sufficient for the diagnosis of residual myocardial viability. Post-systolic shortening may be explained in part by passive recoil, which releases energy stored in the scar tissue during systolic intra-ventricular unloading. Circumferential fiber shortening appears best suited for characterization of regional deformation, whereas radial displacement and rotation are more dependent on tethering effects, and thus, are more likely to reflect global chamber mechanics.
Authors:
Salome Ryf; Andrea K Rutz; Peter Boesiger; Juerg Schwitter
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance     Volume:  8     ISSN:  1097-6647     ISO Abbreviation:  J Cardiovasc Magn Reson     Publication Date:  2006  
Date Detail:
Created Date:  2006-06-07     Completed Date:  2006-07-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9815616     Medline TA:  J Cardiovasc Magn Reson     Country:  United States    
Other Details:
Languages:  eng     Pagination:  445-51     Citation Subset:  IM    
Affiliation:
Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
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MeSH Terms
Descriptor/Qualifier:
Analysis of Variance
Case-Control Studies
Contrast Media
Gadolinium DTPA / diagnostic use
Humans
Magnetic Resonance Imaging / methods*
Male
Middle Aged
Myocardial Contraction / physiology
Myocardial Infarction / physiopathology*
Systole / physiology*
Chemical
Reg. No./Substance:
0/Contrast Media; 80529-93-7/Gadolinium DTPA

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


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