Document Detail

QT peak dispersion, not QT dispersion, is a more useful diagnostic marker for detecting exercise-induced myocardial ischemia.
MedLine Citation:
PMID:  16567289     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The electrocardiographic indices of QT dispersion (QTd), QT peak dispersion (QTpd), and the principal component analysis ratio (PCAr) are related to the occurrence of fatal arrhythmia and are influenced by physical exercise. OBJECTIVE: The purpose of this study was to investigate whether or not the QT parameters can be used as markers for exercise-induced myocardial ischemia. METHODS: We measured these QT parameters at rest and at 3 minutes after exercise using exercise-stress thallium-201 scintigraphy (SPECT), compared with conventional ST segment changes in 161 patients with suspected or known coronary artery disease. The patients were classified into four groups (normal, redistribution, fixed defect, and redistribution with fixed defect) according to SPECT. RESULTS: At rest, QTd and PCAr were greater in the fixed defect and redistribution with fixed defect groups. PCAr, however, increased after exercise in the redistribution and redistribution with fixed defect groups. Although QTpd at rest was not significantly different among the four groups, it increased in the redistribution and redistribution with fixed defect groups after exercise (QTpd after exercise: normal, 36 +/- 16 ms vs. redistribution, 51 +/- 23 ms, redistribution with fixed defect, 53 +/- 19 ms; P<.05). For myocardial infarction reflected by fixed defect, QTd at rest was the most useful indicator, while QTpd after exercise was the most useful indicator for exercise-induced myocardial ischemia according to multiple logistic regression analysis with receiver operating characteristic curves. In addition, the change in PCAr by exercise was an independent predictor for exercise-induced ischemia. CONCLUSIONS: QTpd and PCAr could be useful indices for exercise-induced myocardial ischemia. Determining the QTpd of a patient after exercising can improve the diagnostic accuracy of ischemia in a routine clinical setting.
Nobuyuki Masaki; Bonpei Takase; Takemi Matsui; Shigeru Kosuda; Fumitaka Ohsuzu; Masayuki Ishihara
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Heart rhythm : the official journal of the Heart Rhythm Society     Volume:  3     ISSN:  1547-5271     ISO Abbreviation:  Heart Rhythm     Publication Date:  2006 Apr 
Date Detail:
Created Date:  2006-03-28     Completed Date:  2006-09-21     Revised Date:  2009-10-27    
Medline Journal Info:
Nlm Unique ID:  101200317     Medline TA:  Heart Rhythm     Country:  United States    
Other Details:
Languages:  eng     Pagination:  424-32     Citation Subset:  IM    
National Defense Medical College Research Institute, Division of Biomedical Engineering, Tokorozawa Japan.
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MeSH Terms
Aged, 80 and over
Coronary Artery Disease / diagnosis,  physiopathology
Heart Conduction System / physiopathology*
Logistic Models
Middle Aged
Myocardial Ischemia / diagnosis*,  physiopathology*,  radionuclide imaging
Predictive Value of Tests
ROC Curve
Research Design
Severity of Illness Index
Thallium Radioisotopes / diagnostic use
Tomography, Emission-Computed, Single-Photon* / methods
Reg. No./Substance:
0/Thallium Radioisotopes
Comment In:
Heart Rhythm. 2006 Apr;3(4):433-4   [PMID:  16567290 ]

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

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