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Xue J, Rowlandson I. The detection of T-wave variation linked to arrhythmic risk: an industry perspective. J Electrocardiol 2013; 46:597-607. [PMID: 24210024 DOI: 10.1016/j.jelectrocard.2013.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Indexed: 01/10/2023]
Abstract
Although the scientific literature contains ample descriptions of peculiar patterns of repolarization linked to arrhythmic risk, the objective quantification and classification of these patterns continues to be a challenge that impacts their widespread adoption in clinical practice. To advance the science, computerized algorithms spawned in the academic environment have been essential in order to find, extract and measure these patterns. However, outside the strict control of a core lab, these algorithms are exposed to poor quality signals and need to be effective in the presence of different forms of noise that can either obscure or mimic the T-wave variation (TWV) of interest. To provide a practical solution that can be verified and validated for the market, important tradeoffs need to be made that are based on an intimate understanding of the end-user as well as the key characteristics of either the signal or the noise that can be used by the signal processing engineer to best differentiate them. To illustrate this, two contemporary medical devices used for quantifying T-wave variation are presented, including the modified moving average (MMA) for the detection of T-wave Alternans (TWA) and the quantification of T-wave shape as inputs to the Morphology Combination Score (MCS) for the trending of drug-induced repolarization abnormalities.
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GREEN DRDARREN. LETTER TO THE EDITOR. Pacing Clin Electrophysiol 2012. [DOI: 10.1111/j.1540-8159.2012.03422.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zizek D, Cvijic M, Tasic J, Jan M, Frljak S, Zupan I. Effect of cardiac resynchronization therapy on beat-to-beat T-wave amplitude variability. Europace 2012; 14:1646-52. [DOI: 10.1093/europace/eus055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Dorenkamp M, Breitwieser C, Morguet AJ, Seegers J, Behrens S, Zabel M. T-wave alternans testing in pacemaker patients: comparison of pacing modes and long-term prognostic relevance. Pacing Clin Electrophysiol 2011; 34:1054-62. [PMID: 21501180 DOI: 10.1111/j.1540-8159.2011.03101.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND T-wave alternans (TWA) is a useful method for identifying patients who are at risk for sudden cardiac death. We aimed to determine the effects of different pacing modes on test results and long-term prognostic relevance of TWA in patients following a dual-chamber (DDD) pacemaker implantation. METHODS Sixty-three patients (mean age 68 ± 13 years) with structural heart disease and recently implanted DDD pacemakers were enrolled. Left ventricular (LV) function was normal or moderately impaired (mean LV ejection fraction 61 ± 13%). All patients underwent sequential TWA testing using atrial and ventricular pacing. RESULTS During atrial pacing requiring physiologic conduction to the ventricles, 21% of TWA tests were positive, 43% negative, and 36% indeterminate. When using right ventricular (RV) pacing in the same patients, 19% of tests were positive, 40% negative, and 41% indeterminate. When positive and indeterminate tests were grouped as nonnegative, the concordance between atrial and ventricular pacing was 62% (κ= 0.22). After a mean follow-up of 5.9 ± 1.9 years, 18 (29%) patients had died. Improved survival was predicted by a negative TWA test using atrial pacing (P = 0.028), but not with ventricular pacing (P = 0.722). CONCLUSIONS In patients with dual-chamber pacemakers, there is a low concordance of TWA test results between atrial pacing with intrinsic conduction to the ventricles and apical RV pacing via pacemaker electrode. However, TWA during atrial pacing clearly exerts long-term prognostic relevance in a patient group with preserved LV function and structural heart disease.
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Affiliation(s)
- Marc Dorenkamp
- Department of Cardiology and Pneumology, Heart Center, Georg-August-University of Göttingen, Göttingen, Germany.
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Selvaraj RJ, Suszko AM, Subramanian A, Sivananthan D, Hill A, Nanthakumar K, Chauhan VS. Body surface projection of action potential duration alternans: A combined clinical–modeling study with implications for improving T-wave alternans detection. Heart Rhythm 2009; 6:1211-9. [DOI: 10.1016/j.hrthm.2009.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 04/01/2009] [Indexed: 10/20/2022]
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Madias JE. QT-Interval Variability and/or T-Wave Alternans. Ann Noninvasive Electrocardiol 2009; 14:309-10. [DOI: 10.1111/j.1542-474x.2009.00312.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Madias JE. Prediction of fatal or near fatal arrhythmias in patients with a depressed left ventricular function after an acute myocardial infarction. Eur Heart J 2009; 30:1288. [DOI: 10.1093/eurheartj/ehp166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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MINKKINEN MIKKO, KÄHÖNEN MIKA, VIIK JARI, NIKUS KJELL, LEHTIMÄKI TERHO, LEHTINEN RAMI, KÖÖBI TIIT, TURJANMAA VÄINÖ, KAISER WILLI, VERRIER RICHARDL, NIEMINEN TUOMO. Enhanced Predictive Power of Quantitative TWA during Routine Exercise Testing in the Finnish Cardiovascular Study. J Cardiovasc Electrophysiol 2009; 20:408-15. [DOI: 10.1111/j.1540-8167.2008.01325.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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T-wave alternans in risk stratification of patients with nonischemic dilated cardiomyopathy: Can it help to better select candidates for ICD implantation? Heart Rhythm 2009; 6:S29-35. [DOI: 10.1016/j.hrthm.2008.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Indexed: 11/13/2022]
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Garcia EDV. T-wave alternans: reviewing the clinical performance, understanding limitations, characterizing methodologies. Ann Noninvasive Electrocardiol 2009; 13:401-20. [PMID: 18973498 DOI: 10.1111/j.1542-474x.2008.00254.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Accurate recognition of individuals at higher immediate risk of sudden cardiac death (SCD) is still an open question. The fortuitous nature of acute cardiovascular events just does not seem to fit the well-known model of ventricular tachycardia/fibrillation induction in a static arrhythmogenic substrate by a synchronous trigger. On the mechanism of SCD, a dynamical electrical instability would better explain the rarity of the simultaneous association of a correct trigger and an appropriate cardiac substrate. Several studies have been conducted trying to measure this cardiac electrical instability (or any valid surrogate) in an ECG beat stream. Among the current possible candidates we can number QT prolongation, QT dispersion, late potentials, T-wave alternans (TWA), and heart rate turbulence. This article reviews the particular role of TWA in the current cardiac risk stratification scenario. TWA findings are still heterogeneous, ranging from very good to nearly null prognostic performance depending on the clinical population observed and clinical protocol in use. To fill the current gaps in the TWA base of knowledge, practitioners, and researchers should better explore the technical features of the several technologies available for TWA evaluation and pay greater attention to the fact that TWA values are responsive to several factors other than medications. Information about the cellular and subcellular mechanisms of TWA is outside the scope of this article, but the reader is referred to some of the good papers available on this topic whenever this extra information could help the understanding of the concepts and facts covered herein.
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Affiliation(s)
- Euler de Vilhena Garcia
- The Heart Institute (InCor), University of São Paulo Medical School - Electrocardiology Service, São Paulo, Brazil.
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Madias JE. To the Editor. Heart Rhythm 2008; 5:e1. [DOI: 10.1016/j.hrthm.2008.03.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Indexed: 11/26/2022]
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Cuesta-Frau D, Micó-Tormos P, Aboy M, Biagetti MO, Austin D, Quinteiro RA. Enhanced modified moving average analysis of T-wave alternans using a curve matching method: a simulation study. Med Biol Eng Comput 2008; 47:323-31. [PMID: 18936998 DOI: 10.1007/s11517-008-0415-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 10/02/2008] [Indexed: 10/21/2022]
Abstract
T-wave alternans (TWA) are beat-to-beat amplitude oscillations in the T-waves of electrocardiograms (ECGs). Numerous clinical studies have demonstrated the link between these oscillations and ventricular arrhythmias. Several methods have been developed in recent years to detect and quantify this important feature. Most methods estimate the amplitude differences between pairs of consecutive T-waves. One such method is known as modified moving average (MMA) analysis. The TWA magnitude is obtained by means of the maximum absolute difference of even and odd heartbeat series averages computed at T-waves or ST-T complexes. This method performs well for different levels of TWA, noise, and phase shifts, but it is sensitive to the alignment of the T-waves. In this paper we propose a preprocessing stage for the MMA method to ensure an optimal alignment of such averages. The alignment is performed by means of a continuous time warping technique. Our assessment study demonstrates the improved performance of the proposed algorithm.
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Affiliation(s)
- D Cuesta-Frau
- Technological Institute of Informatics, Polytechnic University of Valencia, Campus Alcoi Plaza Ferrándiz y Carbonell, 2, 03801 Alcoi, Spain.
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Madias JE. T-wave alterans magnitude, T-wave amplitude, and heart rate. Commentary on "Characterization of T wave alterans with ambulatory electrocardiography". Biol Res Nurs 2008; 9:269-70; discussion 271. [PMID: 18411490 DOI: 10.1177/1099800408315161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- John E Madias
- Mount Sinai School of Medicine of New York University and the Division of Cardiology, Elmhurst Hospital Center, NY, USA.
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T-Wave Alternans and Intraventricular Conduction Delays. J Am Coll Cardiol 2008; 51:969-70. [DOI: 10.1016/j.jacc.2007.08.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 08/09/2007] [Indexed: 11/24/2022]
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Kumar K, Kwaku KF, Verrier RL. Treatment options for patients with coronary artery disease identified as high risk by T-wave alternans testing. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2008; 10:39-48. [DOI: 10.1007/s11936-008-0005-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Madias JE. Manual-based versus automation-based measurements of the amplitude of QRS complexes and T waves in patients with changing edematous states: clinical implications. J Electrocardiol 2008; 41:15-8. [PMID: 17631891 DOI: 10.1016/j.jelectrocard.2007.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Accepted: 05/11/2007] [Indexed: 10/23/2022]
Abstract
Most of the previous work pertaining to the impact of peripheral edema on the ECG has been based on manual measurements. Comparison of manual- and automation-based measurements of P waves has been previously carried out. The objective of this study was to compare manual and automated measurements of QRS complexes and T waves. The sum of the amplitude of QRS complexes for manual (SigmaQRSm) and automated (SigmaQRSa) and for T waves for manual (SigmaTm) and automated (SigmaTa) measured in the 12-leads of the ECGs was calculated in 28 patients with peripheral edema and 28 controls, without change in their weight during hospitalization; data points (n = 125) from all phases of the study were lamped together. SigmaQRSm was 114.1 +/- 46.2, and SigmaQRSa was 125.4 +/- 49.5 (n = 125); correlation of SigmaQRSm and SigmaQRSa was excellent (r = 0.98, P = .00005). SigmaTm was 18.1 +/- 13.3, and SigmaTa was 19.8 +/- 12.7 (n = 125); correlation of SigmaTm and SigmaTa was excellent (r = 0.96, P = .00005). Correlations of SigmaQRSm and SigmaTm (r = 0.43, P = .0002), as well as SigmaQRSa and SigmaTa (r = 0.49, P = .00005) were fair to moderately good, correspondingly. Manual and automated measurements of the sums of the amplitudes of the QRS complexes and T waves are well correlated and differ by approximately 9%, with the manual measurements generating lower values. Automated measurements of the QRS complexes and T waves are reliable and can be used in the diagnosis and monitoring of patients showing changes in the amplitude of these 2 components of the ECG curve.
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Affiliation(s)
- John E Madias
- Mount Sinai School of Medicine, New York University, New York, NY, USA.
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Verrier RL, Kumar K, Josephson ME. The frustrating search for arrhythmia risk stratifiers in heart failure due to nonischemic cardiomyopathy: does T-wave alternans testing help? J Am Coll Cardiol 2007; 50:1905-6. [PMID: 17980259 DOI: 10.1016/j.jacc.2007.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 08/31/2007] [Accepted: 09/07/2007] [Indexed: 01/24/2023]
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Madias JE. T-Wave Amplitude Attenuation/Augmentation in Patients With Changing Edematous States: Implications for Patients With Congestive Heart Failure. ACTA ACUST UNITED AC 2007; 13:257-61. [DOI: 10.1111/j.1527-5299.2007.06212.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chattipakorn N, Incharoen T, Kanlop N, Chattipakorn S. Heart rate variability in myocardial infarction and heart failure. Int J Cardiol 2007; 120:289-96. [PMID: 17349699 DOI: 10.1016/j.ijcard.2006.11.221] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 11/20/2006] [Accepted: 11/21/2006] [Indexed: 12/11/2022]
Abstract
The need to refine the identification of patients who might benefit from implantation of an implantable cardioverter defibrillator has been risen by the results of many clinical trials on ICD therapy. Traditional parameters such as left ventricular ejection fraction and the presence of non-sustained ventricular tachycardia were not strong enough to achieve this goal with reasonable cost-effectiveness. Heart rate variability (HRV) is one of the most popular parameters used to assess the autonomic tone. HRV has been reported as a strong predictor of cardiovascular mortality. Currently, three different categories of methods in HRV analysis are being used; the time domain, frequency domain, and non-linear dynamic analysis. Both time domain and frequency domain analyses of HRV have been investigated extensively regarding their use as a prognostic marker for cardiovascular mortality. The non-linear dynamic analysis is the latest tool that has shown to have an even higher predictive value than any of the traditional parameters. However, standardized and supporting evidence on this new technique is still lacking. In this article, the current role of HRV in the prediction of cardiovascular mortality in myocardial infarction and heart failure patients has been reviewed.
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Affiliation(s)
- Nipon Chattipakorn
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
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Reproducibility of the T-wave alternans and dependence of T-wave alternans on the T-wave amplitude: 2 issues requiring immediate attention. J Electrocardiol 2006; 40:364.e1-3. [PMID: 17010365 DOI: 10.1016/j.jelectrocard.2006.08.097] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 08/02/2006] [Indexed: 11/24/2022]
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Grimm W. Quantitative assessment on microvolt T-wave alternans (MTWA) in 204 consecutive patients with congestive heart failure. J Cardiovasc Electrophysiol 2005; 16:1263; author reply 1263-4. [PMID: 16302917 DOI: 10.1111/j.1540-8167.2005.326_1.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Affiliation(s)
- Sergio Richter
- Department of Cardiology, Division of Clinical Electrophysiology, J.W. Goethe University, Theodor-Stern-Kai 7, D-60590 Frankfurt, Germany
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Verrier RL, Kwaku KF, Nearing BD, Josephson ME. Reply to the Editor:. J Cardiovasc Electrophysiol 2005. [DOI: 10.1111/j.1540-8167.2005.326_3.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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