Journal article
The many faces of repolarization instability: which one is prognostic?
Journal of electrocardiology, Vol.42(6), pp.511-516
2009
DOI: 10.1016/j.jelectrocard.2009.06.008
PMCID: PMC2767468
PMID: 19717165
Abstract
Instabilities of the STT segment's magnitude, and particularly the 0.5 beat/cycle oscillations (T-wave alternans, or TWA), have been linked to the heightened risk of ventricular tachyarrhythmias (VTA) and sudden cardiac death (SCD). During the last decade theoretical, experimental and clinical research efforts have focused primarily on TWA, examining its mechanisms and predictive value using time-invariant cutoff values. However, recent evidence suggests that such a single-snapshot test of a single-frequency (TWA) oscillation using a constant cutoff value might be suboptimal for risk stratification because of several reasons.
First, it is well known that the risk of VTA/SCD evolves over time with changes in electrophysiologic substrate, environmental and physiologic triggers, and the impact of other physiologic (eg, circadian) rhythmicity. Hence, the outcome of TWA testing might depend on the time of day, as Holter-based TWA studies have demonstrated. Furthermore, currently used single-snapshot testing with a binary cutoff value may not coincide with the periods of heightened risk for VTA/SCD and may not yield prognostic information, as a recent TWA substudy of the sudden cardiac death in heart failure trial has showed. Second, the analysis focused on TWA alone ignores the existence of multiple (alternating and nonalternating) forms of repolarization instability that have been shown to arise or increase before the onset of VTA/SCD.
Summarizing, recent studies have identified multiple forms of repolarization instabilities modulated by distinct mechanisms, which might have different prognostic values. Therefore, the assessment of TWA needs to be dynamic and personalized to take into account the time evolution of risk and individual history.
Details
- Title: Subtitle
- The many faces of repolarization instability: which one is prognostic?
- Creators
- Vladimir Shusterman - University of Pittsburgh, Pittsburgh, PA, USARachel Lampert - Yale University, New Haven, CT, USABarry London - University of Pittsburgh, Pittsburgh, PA, USA
- Resource Type
- Journal article
- Publication Details
- Journal of electrocardiology, Vol.42(6), pp.511-516
- DOI
- 10.1016/j.jelectrocard.2009.06.008
- PMID
- 19717165
- PMCID
- PMC2767468
- NLM abbreviation
- J Electrocardiol
- ISSN
- 0022-0736
- eISSN
- 1532-8430
- Publisher
- Elsevier Inc
- Language
- English
- Date published
- 2009
- Academic Unit
- Molecular Physiology and Biophysics; Cardiovascular Medicine; Internal Medicine
- Record Identifier
- 9984025372702771
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