Document Detail

Left precordial isopotential mapping during supine exercise.
MedLine Citation:
PMID:  872317     Owner:  NLM     Status:  MEDLINE    
Junctional depression is often observed during physical exercise in overtly normal subjects. To explore its pathogenesis, 15 normal volunteers were studied during supine, bicycle ergometer, submaximal stress tests. Electrocardiograms were simultaneously recorded from 42 electrodes on the left anterior precordium at two minute intervals at rest and during exercise. Data were used to construct isopotential maps throughout the P-QRS-T intervals. At rest, maps throughout the ST segment were dominated by a single maximum along the upper left sternal border. During exercise, all subjects developed junctional depression that was maximal along the lower left sternal border. Exercise maps during the early to mid-ST segment showed an intense minimum along the lower left sternal border that was continuous with terminal QRS forces in both intensity and location. Later in ST, this minimum decreased in strength and was replaced by a maximum located in the same area as that observed at rest. These observations suggest that junctional depression is the result of competition between two effects, one being normal repolarization which is obscured in the early ST segment by the second, possibly representing delayed terminal depolarization forces.
D M Mirvis; F W Keller; J W Cox; D G Zettergren; R F Dowdie; R E Ideker
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation     Volume:  56     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1977 Aug 
Date Detail:
Created Date:  1977-09-02     Completed Date:  1977-09-02     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  245-52     Citation Subset:  AIM; IM    
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MeSH Terms
Action Potentials*
Heart / physiology*
Physical Exertion*
Thorax / physiology

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

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