Document Detail

In vivo validation of longitudinal-circumferential area change ratio to estimate myofiber shortening in the heart.
MedLine Citation:
PMID:  22345526     Owner:  NLM     Status:  Publisher    
The aim of the present study was to validate area change ratio (%AC) against myofiber shortening (%ë f) in the heart in vivo. %AC is emerging as a mechanical index that may approximate %ë f by incorporating both circumferential and longitudinal shortening. However, the physiological significance of %AC remains unclear. We studied the time course of %AC in the anterior mid-left ventricular wall of normal canine heart in vivo (n=14) during atrial pacing over the entire cardiac cycle using transmurally implanted markers and biplane cineradiography (8 msec/frame). %AC was calculated as the myocardial area change relative to the elemental material area on the circumferential- longitudinal plane at the reference configuration (= end diastole). %AC was compared with %ë f that was determined from the transmural fiber orientation directly measured in the heart tissue. The time course of both %AC and %ë f was determined in the subepicardial, midwall, and subendocardial layers. The time course of %AC and %ë f was significantly different, and the difference was more pronounced towards the endocardium. %AC consistently overestimated %ë f. The timing of the peak %AC was significantly delayed compared to that of the peak %ë f. We conclude that %AC is significantly different from %ë f both in magnitude and timing in vivo. %AC overestimates %ë f, and the overestimation is worse towards the endocardial layers. This may be a potentially important limitation when applying %AC to optimization and responder identification for cardiac resynchronization therapy.
H Ashikaga; J Omens
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-2-15
Journal Detail:
Title:  IEEE transactions on bio-medical engineering     Volume:  -     ISSN:  1558-2531     ISO Abbreviation:  -     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-2-20     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0012737     Medline TA:  IEEE Trans Biomed Eng     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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