Electrical Alternans and Vulnerability to Ventricular Arrhythmias

Rosenbaum, David S.; Jackson, Lance E.; Smith, Joseph M.; Garan, Hasan; Ruskin, Jeremy N.; Cohen, Richard J.

doi:10.1056/nejm199401273300402

Cited by 1,012 publications

(725 citation statements)

References 29 publications

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“…19,23 TWA has been shown to reflect the presence of abnormal repolarization and electrophysiologic inhomogeneities that underlie vulnerability to ventricular fibrillation. 19 Measurement of TWA during controlled heart rate elevation is considered as a potentially useful predictor of ventricular arrhythmic events and mortality in patients with ischemic cardiomyopathy, 3 and its role in identification of patients that would benefit ICD implantation is being currently studied.…”

Section: Introductionmentioning

confidence: 99%

“…Several methods exist to automatically detect and estimate TWA. 12 Two commercially available techniques are the spectral method (SM) 23,26 and the modified moving average method 22 ; alternative techniques are the complex demodulation method 20 and the Laplacian likelihood ratio method (LLR). 11,13 A major limitation of these methods is their poor sensitivity to low-amplitude alternans 12,19 due to a lack of robustness to noise.…”

Section: Introductionmentioning

confidence: 99%

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A Multilead Scheme Based on Periodic Component Analysis for T-Wave Alternans Analysis in the ECG

et al. 2010

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Abstract-T-wave alternans (TWA) is a cardiac phenomenon that appears in the electrocardiogram (ECG) and is associated with the mechanisms leading to sudden cardiac death (SCD). In this study, we propose the use of a multilead TWA analysis scheme that combines the Laplacian likelihood ratio (LLR) method and periodic component analysis (pCA), an eigenvalue decomposition technique whose aim is to extract the most periodic sources of the signal. The proposed scheme is evaluated in different scenarios-from synthetic signals to stress test ECGs-and is compared to other reported schemes based on the LLR method. Results demonstrate that the pCA-based scheme provides a superior ability to detect TWA than previously reported schemes, and has the potential to improve the prognostic value of testing for TWA.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Multilead Scheme Based on Periodic Component Analysis for T-Wave Alternans Analysis in the ECG

et al. 2010

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“…Furthermore, clinical studies suggest that there is a high correlation between large amplitude microscopic TWA and sudden cardiac arrest. 5,6 Despite growing empiric evidence that microscopic TWA is an important clinical measure of cardiac electrical instability, its exact mechanism is unproven. Alternans of action potential duration (APD) and refractory period is well known to occur in cardiac tissue at high rates, so TWA could well be an ECG manifestation of APD alternans.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms for Discordant Alternans

Watanabe

Fenton

Evans

et al. 2001

Cardiovasc electrophysiol

305

360

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Discordant Alternans Mechanism. Introduction: Discordant alternans has the potential to produce larger alternans of the ECG T wave than concordant alternans, but its mechanism is unknown. Methods and Results:We demonstrate by one-and two-dimensional simulation of action potential propagation models that discordant alternans can form spontaneously in spatially homogeneous tissue through one of two mechanisms, due to the interaction of conduction velocity and action potential duration restitution at high pacing frequencies or through the dispersion of diastolic interval produced by ectopic foci. In discordant alternans due to the rst mechanism, the boundaries marking regions of alternans with opposite phase arise far from the stimulus site, move toward the stimulus site, and stabilize. Dynamic splitting of action potential duration restitution curves due to electrotonic coupling plays a crucial role in this stability. Larger tissues and faster pacing rates are conducive to multiple boundaries, and inhomogeneities of tissue properties facilitate or inhibit formation of boundaries.Conclusion: Spatial inhomogeneities of electrical restitution properties are not required to produce discordant alternans.

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“…The first one, which is regarded as the gold-standard algorithm, is based on the periodogram proposed in Smith et al (1988) [5,6]. In this method, ST-T segments of 128 beats are aligned, and the periodogram-based cycle per beat (cpb) frequency analysis is performed for each sample.…”

Section: Previous Research On Quantification Of T-wave Alternansmentioning

confidence: 99%

Fractal-Dimension-Based Method for Quantification of T-Wave Alternans Using Short Time Series

Sakai¹

2013

J Comput Sci Syst Biol

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The presence of T-Wave Alternans (TWA) in an electrocardiogram (ECG) has been certified as an important predictor for the risk of sudden cardiac death (SCD). TWA is a beat-to-beat change in the amplitude of a T-wave, but is rarely visible to the naked eye. Thus, automatic detection and quantification of TWA are desirable. While several automatic algorithms, such as the periodogram method or the modified moving average method (MMA), have been developed to detect or quantify TWA, most conventional methods do not effectively measure short-duration TWA (SDTWA) (<16 beats). In this paper, we proposed a fractal dimension based SDTWA quantification method, and evaluated it with simulated ECG signals with SDTWA episodes (<16 beats) based on the European ST-T database. In the evaluation, the proposed method was applied to ECG signals with TWA amplitude of 5, 15, 30, 45, 60 and 75 μV. Sensitivity and positive predictivity of over or closed to 90% were obtained except for the 5 μV SDTWA episodes. Even for 5 μV SDTWA episodes, the sensitivity reached 75%. We believe that proposed s fractal dimension based method is a promising method for SDTWA analysis.

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Electrical Alternans and Vulnerability to Ventricular Arrhythmias

Abstract: Electrical alternans affecting the ST segment and T wave is common among patients at increased risk for ventricular arrhythmias. Subtle electrical alternans on the electrocardiogram may serve as a noninvasive marker of vulnerability to ventricular arrhythmias.

Cited by 1,012 publications

References 29 publications

A Multilead Scheme Based on Periodic Component Analysis for T-Wave Alternans Analysis in the ECG

A Multilead Scheme Based on Periodic Component Analysis for T-Wave Alternans Analysis in the ECG

Mechanisms for Discordant Alternans

Fractal-Dimension-Based Method for Quantification of T-Wave Alternans Using Short Time Series

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