Document Detail


Predictive value of T-wave morphology variables and QT dispersion for postmyocardial infarction risk assessment.
MedLine Citation:
PMID:  11781933     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Different attempts have been made to use the 12-lead surface electrocardiogram (ECG) for risk stratification of patients prone to sudden cardiac death. Among others, QT dispersion (QTd) has been proposed as a simple risk marker, eg, in patients postmyocardial infarction (MI). To overcome the methodological limitations of QTd, novel T-wave morphology variables have been recently developed based on technologies that better quantify the substrate of a pathologically changed repolarization. In 280 post-MI patients with 27 events (death or nonfatal sustained ventricular tachycardia/ventricular fibrillation) during long-term follow-up (32 +/- 10 months), a 12-lead ECG was recorded before discharge and converted into a digital format. The prognostic value of digitally measured QTd and other conventional variables, and that of novel ECG variables of T-wave loop morphology was assessed. The latter included fully automatic and reproducible analysis of variables defining spatial and temporal T-wave variation as well as its wavefront direction. Among the 5 variables studied, the total cosine R to T (TCRT--describing the global angle between repolarization and depolarization orientations) and the T-wave loop dispersion were univariately associated (P = .0002 and P < .002) with events. Comparison of Kaplan Meier curves for patient strata above and below the median confirmed the strong discrimination of risk by TCRT and T-wave loop dispersion values (P < .003 and P < .001). On Cox regression analysis entering other univariately predictive risk stratifiers including age, left ventricular ejection fraction, heart rate, reperfusion therapy, beta adrenergic blocker treatment, and SDNN from Holter, TCRT (P < .03) yielded independent predictive value while T-wave loop dispersion was of borderline independence (P = .064). Heart rate (P < .02), left ventricular ejection fraction (P < .02), and reperfusion therapy (P <.02) also remained in the final model. In contrast, none of the conventional variables of repolarization dispersion including QTd and rate-corrected QTd revealed prognostic value on univariate or Kaplan Meier analysis despite optimized digital processing techniques. Computerized analysis of T-wave loop morphology from the 12-lead resting ECG permits independent assessment of post-MI risk and should replace the poorly conceptualized measurement of QTd.
Authors:
M Zabel; M Malik
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of electrocardiology     Volume:  34 Suppl     ISSN:  0022-0736     ISO Abbreviation:  J Electrocardiol     Publication Date:  2001  
Date Detail:
Created Date:  2002-01-08     Completed Date:  2002-02-13     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0153605     Medline TA:  J Electrocardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  27-35     Citation Subset:  IM    
Affiliation:
Division of Cardiology, Benjamin Franklin Hospital, Free University of Berlin, Berlin, Germany. mzabel@compuserve.com
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MeSH Terms
Descriptor/Qualifier:
Death, Sudden, Cardiac* / epidemiology
Electrocardiography*
Female
Follow-Up Studies
Humans
Male
Middle Aged
Myocardial Infarction / diagnosis*
Prognosis
Proportional Hazards Models
Risk Assessment
Risk Factors
Signal Processing, Computer-Assisted*
Time Factors

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


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