Linked Life Data

2801973

Source:http://linkedlifedata.com/resource/pubmed/id/2801973

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4 Pt 2
pubmed:dateCreated
1989-11-17
pubmed:abstractText
Cardiac models have proposed tight coupling between the systolic twisting motion of the left ventricle about its longitudinal axis and muscle shortening. Whether a similar relationship holds during diastole is unknown. The present study determined the dynamic twist-radial shortening relationship throughout the cardiac cycle in six in situ canine left ventricles. Radiopaque markers (15-26) were implanted throughout the myocardial midwall in six canine left ventricles. Three-dimensional marker location was determined by computer analysis of biplane cineradiograms (60 frames/s), and the results were transformed to cardiac cylindrical coordinates. Mean chamber twist was defined as the gradient along the long axis of circumferential rotation relative to end diastole. Changes in chamber dimension were indexed by average radial shortening, normalized to span from 0 at end diastole to 1.0 at end systole. During systole, ventricular twist and radial shortening were linearly related with an average slope of -0.058 radians (r = 0.99). However, during early diastolic relaxation there was substantial untwist (48 +/- 20% of total) despite only an approximately 15% increase in mean radial dimension resulting in a much steeper twist-percent shortening relationship (-0.24 radians, r = 0.96). During most of the remainder of diastolic filling, the twist-shortening relation was shallower (-0.02, r = 0.91) than the corresponding systolic relation (P less than 0.05). Thus the twist-radial shortening relation depends on the phase of the cardiac cycle. These data suggest that models of chamber mechanics that incorporate twisting motion need to account for the matrix surrounding the muscles in addition to the shortening and lengthening of the muscle fibers.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
257
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H1119-26
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Dependence of left ventricular twist-radial shortening relations on cardiac cycle phase.
pubmed:affiliation
Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.