RT-170
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T-wave alternans: will it
revolutionize risk stratification for sudden cardiac death?
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Hans D. Esperer, Helmut U. Klein,
Richard J. Cohen*.
Dept. of Internal Medicine, Division of Cardiology, Otto-von-Guericke, Magdeburg
University, Germany, *Harvard University, MIT Division of Health Sciences and Technology,
Cambridge, MA, USA
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Introduction
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Approximately 300 000 patients die each year of sudden
cardiac death (SCD) in the United States alone. The vast majority of these cases is due to
ventricular tachycardia (VT) or ventricular fibrillation (VF). The implantable
cardioverter-defibrillator (ICD) provides a very efficient means for termination of these
tachyarrhythmias and prevention of SCD. The classical markers of risk stratification, such
as left ventricular ejection fraction, frequent and/or complex ventricular ectopic
complexes, and late ventricular potentials, though very specific, suffer from poor
positive predictive accuracy. Although assessment of heart rate variability, especially in
combination with LVEF, VPC and VLP has significantly improved risk prediction, its
positive predictive accuracy is generally low1.
Recently, assessment of repolarization alternans (TWA) in the electrocardiogram has become
possible. TWA by definition is characterized by changes in contour, amplitude, or polarity
of the T-wave, appearing with regular rhythmicity, usually every other beat, unaccompanied
by a discernible alteration of the QRS complexes or gross changes in the cycle length.
This article focusses on the clinical relevance of TWA with special reference to its
diagnostic efficacy in predicting arrhythmia inducibility.
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Key Words
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Sudden Death
T-wave alternans, mortality risk stratification, prolongation of repolarization,
electrical alternans, left bundle branch block, hypertrophic cardiomyopathy, long QT
syndrome, R
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