Document Detail

Early detection of abnormal left ventricular relaxation in acute myocardial ischemia with a quadratic model.
MedLine Citation:
PMID:  25042155     Owner:  NLM     Status:  Publisher    
AIMS: The time constant of left ventricular (LV) relaxation derived from a monoexponential model is widely used as an index of LV relaxation rate, although this model does not reflect the non-uniformity of ventricular relaxation. This study investigates whether the relaxation curve can be better fitted with a "quadratic" model than with the "conventional" monoexponential model and if changes in the LV relaxation waveform due to acute myocardial ischemia could be better detected with the quadratic model.
METHODS AND RESULTS: Isovolumic relaxation was assessed with quadratic and conventional models during acute myocardial ischemia performed in 6 anesthetized pigs. Mathematical development indicates that one parameter (Tq) of the quadratic model reflects the rate of LV relaxation, while the second parameter (K) modifies the shape of the relaxation curve. Analysis of experimental data obtained in anesthetized pigs showed that the shape of LV relaxation consistently deviates from the conventional monoexponential decay. During the early phase of acute myocardial ischemia, the rate and non-uniformity of LV relaxation, assessed with the quadratic function, were significantly enhanced. Tq increased by 16% (p<0.001) and K increased by 12% (p<0.001) within 30 and 60min, respectively, after left anterior descending (LAD) coronary artery occlusion. However, no significant changes were observed with the conventional monoexponential decay within 60min of ischemia.
CONCLUSIONS: The quadratic model better fits LV isovolumic relaxation than the monoexponential model and can detect early changes in relaxation due to acute myocardial ischemia that are not detectable with conventional methods.
Philippe Morimont; Antoine Pironet; Thomas Desaive; Geoffrey Chase; Bernard Lambermont
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-7-16
Journal Detail:
Title:  Medical engineering & physics     Volume:  -     ISSN:  1873-4030     ISO Abbreviation:  Med Eng Phys     Publication Date:  2014 Jul 
Date Detail:
Created Date:  2014-7-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9422753     Medline TA:  Med Eng Phys     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.
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