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Duca ȘT, Roca M, Costache AD, Chetran A, Afrăsânie I, Miftode RȘ, Tudorancea I, Matei I, Ciorap RG, Mitu O, Bădescu MC, Iliescu-Halitchi D, Halițchi-Iliescu CO, Mitu F, Lionte C, Costache II. T-Wave Analysis on the 24 h Holter ECG Monitoring as a Predictive Assessment of Major Adverse Cardiovascular Events in Patients with Myocardial Infarction: A Literature Review and Future Perspectives. Life (Basel) 2023; 13:life13051155. [PMID: 37240799 DOI: 10.3390/life13051155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/01/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
Myocardial ischemia is a pathophysiological state characterized by inadequate perfusion of the myocardium, resulting in an imbalance between myocardial oxygen demand and supply. It is most commonly caused by coronary artery disease, in which atherosclerotic plaques lead to luminal narrowing and reduced blood flow to the heart. Myocardial ischemia can manifest as angina pectoris or silent myocardial ischemia and can progress to myocardial infarction or heart failure if left untreated. Diagnosis of myocardial ischemia typically involves a combination of clinical evaluation, electrocardiography and imaging studies. Electrocardiographic parameters, as assessed by 24 h Holter ECG monitoring, can predict the occurrence of major adverse cardiovascular events in patients with myocardial ischemia, independent of other risk factors. The T-waves in patients with myocardial ischemia have prognostic value for predicting major adverse cardiovascular events, and their electrophysiological heterogeneity can be visualized using various techniques. Combining the electrocardiographic findings with the assessment of myocardial substrate may offer a better picture of the factors that can contribute to cardiovascular death.
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Affiliation(s)
- Ștefania-Teodora Duca
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
| | - Mihai Roca
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiovascular Rehabilitation, Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Alexandru-Dan Costache
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiovascular Rehabilitation, Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Adriana Chetran
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
| | - Irina Afrăsânie
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
| | - Radu-Ștefan Miftode
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
| | - Ionuț Tudorancea
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
- Department of Morpho-Functional Science II-Physiology, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
| | - Iulian Matei
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
| | - Radu-George Ciorap
- Department of Biomedical Science, Faculty of Medical Bioengineering, University of Medicine and Pharmacy "Grigore T. Popa", 700145 Iasi, Romania
| | - Ovidiu Mitu
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
| | - Minerva Codruța Bădescu
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of III Internal Medicine Clinic, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
| | - Dan Iliescu-Halitchi
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiology, Arcadia Hospital, 700620 Iasi, Romania
| | - Codruța-Olimpiada Halițchi-Iliescu
- Department of Mother and Child Medicine-Pediatrics, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Pedriatics, Arcadia Hospital, 700620 Iasi, Romania
| | - Florin Mitu
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiovascular Rehabilitation, Clinical Rehabilitation Hospital, 700661 Iasi, Romania
| | - Cătălina Lionte
- Department of Internal Medicine III, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700145 Iasi, Romania
- Department of Cardiology, Helicomed Hospital, 700115 Iasi, Romania
| | - Irina-Iuliana Costache
- Department of Internal Medicine I, Faculty of Medicine, University of Medicine and Pharmacy "Grigore T. Popa", 700115 Iasi, Romania
- Department of Cardiology, "St. Spiridon" Emergency County Hospital, 700111 Iasi, Romania
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De Ferrari GM, Sanzo A. 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] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Indexed: 11/13/2022]
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Guo D, Young L, Patel C, Jiao Z, Wu Y, Liu T, Kowey PR, Yan GX. Calcium-activated chloride current contributes to action potential alternations in left ventricular hypertrophy rabbit. Am J Physiol Heart Circ Physiol 2008; 295:H97-H104. [PMID: 18441200 DOI: 10.1152/ajpheart.01032.2007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
T-wave alternans, characterized by a beat-to-beat change in T-wave morphology, amplitude, and/or polarity on the ECG, often heralds the development of lethal ventricular arrhythmias in patients with left ventricular hypertrophy (LVH). The aim of our study was to examine the ionic basis for a beat-to-beat change in ventricular repolarization in the setting of LVH. Transmembrane action potentials (APs) from epicardium and endocardium were recorded simultaneously, together with transmural ECG and contraction force, in arterially perfused rabbit left ventricular wedge preparation. APs and Ca(2+)-activated chloride current (I(Cl,Ca)) were recorded from left ventricular myocytes isolated from normal rabbits and those with renovascular LVH using the standard microelectrode and whole cell patch-clamping techniques, respectively. In the LVH rabbits, a significant beat-to-beat change in endocardial AP duration (APD) created beat-to-beat alteration in transmural voltage gradient that manifested as T-wave alternans on the ECG. Interestingly, contraction force alternated in an opposite phase ("out of phase") with APD. In the single myocytes of LVH rabbits, a significant beat-to-beat change in APD was also observed in both left ventricular endocardial and epicardial myocytes at various pacing rates. APD alternans was suppressed by adding 1 microM ryanodine, 100 microM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), and 100 microM 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS). The density of the Ca(2+)-activated chloride currents (I(Cl,Ca)) in left ventricular myocytes was significantly greater in the LVH rabbits than in the normal group. Our data indicate that abnormal intracellular Ca(2+) fluctuation may exert a strong feedback on the membrane I(Cl,Ca), leading to a beat-to-beat change in the net repolarizing current that manifests as T-wave alternans on the ECG.
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Affiliation(s)
- Donglin Guo
- Main Line Health Heart Ctr., Wynnewood, PA 19096, USA.
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Abstract
Sudden cardiac death (SCD) is the leading cause of mortality in patients with ischemic heart disease and left ventricular dysfunction. The majority of SCD are due to ventricular tachyarrhythmias. SCD strikes many asymptomatic patients and often is the first manifestation of heart disease. Thus, reliable determination of arrhythmic risk is warranted to guide preventive therapy. To highlight the prognostic value of microvolt-level electrical alternans of the T-wave (MTWA) in patients at risk for SCD, most of the pertinent published articles in the Medline, Scopus, and EBSCO Host research databases have been reviewed. MTWA has been proposed to be a strong and independent predictor of all-cause and arrhythmic mortality. The high predictive value of MTWA in patient with cardiomyopathy varies significantly depending on the population studied. Combining with other indices or having serial MTWA readings could overcome MTWA limitations. Redefining MTWA readings may expand its prognostic utility.
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Affiliation(s)
- Ayman El-Menyar
- Department of Cardiology and Cardiovascular Surgery, Hamad General Hospital, Doha, Qatar.
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Abstract
T wave alternans (TWA) is a marker of ventricular electrical instability considered to be predictive for ventricular tachyarrhythmias. Techniques have been developed to detect TWA at the microv level as a method for arrhythmia risk stratification of persons at high risk for sudden cardiac death. Currently, TWA is typically calculated using spectral analysis, whereby TWA is presumed to assume characteristics of stationarity. In contrast, a nonspectral method known as modified moving average analysis is purported to detect transient TWA that would not be observed using a spectral approach. The purpose of this pilot study work was to establish the basic TWA signal properties obtained with a device developed by GE Medical Systems using a descriptive, correlational study design. Ambulatory electrocardiography (AECG) recordings (N = 24) were digitized and processed, and TWA was calculated via the modified moving average technique. Findings showed that noise was positively correlated with TWA in AECG channel 1 (r = .899, p < .01) and AECG channel 2 (r = .758, p < .01). However, no significant difference (p = .237) was observed in TWA values between the AECG channels. A weak positive correlation was found between TWA and heart rate, expressed as beats per min (r = .262). Heart rate mildly predicted TWA (R = 0.34). Nonstationarity was evaluated by testing for trend and randomness. TWA values measured from AECG recordings were found to be influenced moderately by noise and minimally by heart rate and lead placement.
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Affiliation(s)
- Margaret B Harvey
- University of Tennessee Health Science Center, Memphis, TN 38103, USA.
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Lampert R, Soufer R, McPherson CA, Batsford WP, Tirado S, Earley C, Goldberg A, Shusterman V. Implantable Cardioverter-Defibrillator Shocks Increase T-Wave Alternans. J Cardiovasc Electrophysiol 2007; 18:512-7. [PMID: 17428273 DOI: 10.1111/j.1540-8167.2007.00787.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION While implantable defibrillator shocks save lives, shock can lead to ventricular arrhythmias. However, the mechanism of shock-related proarrhythmia remains unclear. We evaluated the impact of ICD shock on repolarization instability, a factor associated with ventricular arrhythmogenesis. METHODS AND RESULTS Sixty-five patients with ICDs underwent ambulatory ECG monitoring during defibrillation testing 3 months postimplant. TWA was analyzed continuously in the time domain during baseline, sedated, and post-shock states. RR, QRS, and QT intervals and catecholamines were also measured continuously. Adequate pre- and post-shock Holter data were recorded in 55 patients, 48 male, mean 64 +/- 12 years, 50 with coronary disease, 48 with prior spontaneous or induced arrhythmia. TWA significantly increased after shock, from 9.6 +/- 0.5 to 11.9 +/- 0.6 microV, as did QRS duration, epinephrine, and norepinephrine levels, compared with sedated and baseline states. RR intervals decreased minimally. TWA changes with shock were not associated with RR or QRS duration changes, but were associated with changes in epinephrine. CONCLUSIONS ICD shock, even in the sedated state, increases repolarization instability as measured by TWA, an effect mediated in part by sympathetic stimulation. This association between shock and TWA may have important mechanistic and clinical implications for optimization of defibrillation therapy.
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Affiliation(s)
- Rachel Lampert
- Department of Medicine, Yale University School of Medicine New Haven, Connecticut, USA.
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Baravelli M, Fantoni C, Rogiani S, Farina S, Anzà C, Caltabiano V, Forzani T, Salerno-Uriarte JA. Combined prognostic value of peak O(2) uptake and microvolt level T-wave alternans in patients with idiopathic dilated cardiomyopathy. Int J Cardiol. 2007;121:23-29. [PMID: 17188766 DOI: 10.1016/j.ijcard.2006.10.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 08/08/2006] [Accepted: 10/14/2006] [Indexed: 01/28/2023]
Abstract
BACKGROUND Despite the great improvement in clinical management of patients with idiopathic dilated cardiomyopathy (DCM), sudden cardiac death (SCD) and death due to worsening heart failure (HF) remain a challenging problem. The assessment of oxygen consumption (peakVO(2)) has been recognized as an independent marker of mortality. Nevertheless peakVO(2) is not helpful in the risk stratification of SCD. Given this limitation, the association with another non-invasive test able to predict SCD such as microvolt level T-wave alternans (MTWA) would be useful. OBJECTIVES To determine the combined predictive value of peakVO(2) and MTWA in patients with DCM. METHODS Seventy consecutive DCM patients were prospectively investigated. PeakVO(2) and MTWA were determined during bicycle exercise testing. Primary composite study end-point was defined as major cardiac events (MCE): total cardiac death or documented sustained VT/VF (including appropriate ICD shock). Secondary end-point was defined as arrhythmic events (AE): SCD or documented sustained VT/VF. RESULTS Thirty-nine patients (55%) had a peakVO(2)<10 ml/kg/min, while 40 patients (57%) showed an abnormal MTWA test. During an average follow-up of 19.2+/-10.7 months, 11 MCE of which 6 AE have been documented. Among patients with abnormal MTWA and peakVO(2)<10 ml/kg/min 8 MCE of which 5 AE occurred while among patients with normal MTWA and peakVO(2)> or =10 ml/kg/min no event occurred. From multivariate analysis, the combined prognostic value of MTWA and peakVO(2) achieved statistical significance for MCE (p=0.03, HR 0.28, 95% CI 0.12-0.95) and for AE (p=0.05, HR 0.39, 95% CI 0.18-0.99) while MTWA alone was a significant predictor of AE (p=0.04, HR 0.32, 95% CI 0.14-0.93). CONCLUSIONS Our results suggest that only the association of MTWA and peakVO(2), but not the two single tests, is a significant prognostic marker of both MCE and AE in DCM patients. However, MTWA alone confirms its predictive power as arrhythmic risk stratifier in this population.
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Abstract
Despite considerable progress in the management of coronary artery disease and dilated cardiomyopathy, a substantial proportion of patients remains at the risk of life-threatening arrhythmic events. The Multicenter Automatic Defibrillator Implantation II and Sudden Cardiac Death Heart Failure studies have conclusively demonstrated that prophylactic implantable cardioverter-defibrillator (ICD) therapy reduces mortality among subjects with ischemic and nonischemic cardiomyopathy but at the expense of potentially unnecessary ICD implantation in a large percentage of patients. Microvolt T-wave alternans (MTWA), with a negative predictive value greater than 90%, holds promise for selecting the patients who would likely and patients not likely to benefit from ICD implantation. Accurate identification of high-risk patients by noninvasive MTWA may allow for improved widespread screening for sudden death prevention in the general population.
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Affiliation(s)
- Majid Haghjoo
- Department of Pacemaker and Electrophysiology, Rajaie Cardiovascular Medical and Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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Abstract
T-wave alternans (TWA) reflects beat-to-beat fluctuations in the electrocardiographic T-wave, and is associated with dispersion of repolarization and the mechanisms for sudden cardiac arrest (SCA). This review examines the bench-to-bedside literature that, over decades, has linked alternans of repolarization in cellular, whole-heart, and human studies with spatial dispersion of repolarization, alternans of cellular action potential, and fluctuations in ionic currents that may lead to ventricular arrhythmias. Collectively, these studies provide a foundation for the clinical use of TWA to reflect susceptibility to ventricular arrhythmias in several disease states. This review then provides a contemporary evidence-based framework for the use of TWA to enhance risk stratification for SCA, identifying populations for whom TWA is best established, those for whom further studies are required, and areas for additional investigation.
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Affiliation(s)
- Sanjiv M Narayan
- San Diego VA Healthcare System, University of California, Whitaker Institute for Biomedical Engineering, Cardiology, San Diego, California 92161, USA.
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Baravelli M, Salerno-Uriarte D, Guzzetti D, Rossi MC, Zoli L, Forzani T, Salerno-Uriarte JA. Predictive significance for sudden death of microvolt-level T wave alternans in New York Heart Association class II congestive heart failure patients. Int J Cardiol 2005; 105:53-7. [PMID: 16207545 DOI: 10.1016/j.ijcard.2004.12.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Revised: 10/10/2004] [Accepted: 12/30/2004] [Indexed: 10/25/2022]
Abstract
BACKGROUND Sudden cardiac death (SDC) is responsible for approximately 60-70% of deaths in New York Heart Association (NYHA) class II congestive heart failure (CHF) patients. Recently, microvolt-level T wave alternans has been proposed as a new noninvasive tool to identify CHF patients at risk for SCD and ventricular tachycardia/fibrillation (VT/VF). OBJECTIVES To determine the prognostic value of MTWA in NYHA class II patients. METHODS Among 181 consecutive CHF patients with ischemic and nonischemic cardiomyopathy, 73 patients in NYHA class II with left ventricular ejection fraction <45% were selected and prospectively investigated. MTWA was determined during bicycle exercise testing. The study end point was defined as SCD, documented sustained VT/VF and appropriate implantable cardioverter defibrillator (ICD) shock. RESULTS MTWA was positive in 30 (41%) patients, negative in 26(36%) patients and indeterminate in 17 (23%) patients. During an average follow-up of 17.1+/-7.4 months, seven patients had an arrhythmic event in the MTWA positive group, whereas one and no events occurred in the indeterminate and negative group, respectively. From Kaplan-Meier univariate analysis and multivariate Cox analysis, MTWA was a significant arrhythmic risk stratifier (p=0.01 and p=0.03, respectively). Sensitivity, specificity, negative and positive predictive values of MTWA were 100%, 53%, 100% and 24%, respectively. CONCLUSION Our data suggest that MTWA is a promising predictor of arrhythmic events in NYHA class II CHF patients.
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Affiliation(s)
- Massimo Baravelli
- Department of Cardiology, University of Insubria, Clinical Institute Mater Domini, Castellanza (VA), Italy.
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Gehi AK, Stein RH, Metz LD, Gomes JA. Microvolt T-Wave Alternans for the Risk Stratification of Ventricular Tachyarrhythmic Events. J Am Coll Cardiol 2005; 46:75-82. [PMID: 15992639 DOI: 10.1016/j.jacc.2005.03.059] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2005] [Revised: 02/22/2005] [Accepted: 03/22/2005] [Indexed: 11/17/2022]
Abstract
OBJECTIVES The objective of this study was to perform a meta-analysis of the predictive value of microvolt T-wave alternans (MTWA) testing for arrhythmic events in a wide variety of populations. BACKGROUND Previous studies describing the use of MTWA as a predictor of ventricular tachyarrhythmic events have been limited by small sample sizes and disparate populations. METHODS Prospective studies of the predictive value of exercise-induced MTWA published between January 1990 and December 2004 were retrieved. Data from each article were abstracted independently by two authors using a standardized protocol. Summary estimates of the predictive value of MTWA were made using a random-effects model. RESULTS Data were accumulated from 19 studies (2,608 subjects) across a wide range of populations. Overall, the positive predictive value of MTWA for arrhythmic events was 19.3% at an average of 21 months' follow-up (95% confidence interval [CI] 17.7% to 21.0%), the negative predictive value was 97.2% (95% CI 96.5% to 97.9%), and the univariate relative risk of an arrhythmic event was 3.77 (95% CI 2.39 to 5.95). There was no difference in predictive value between ischemic and nonischemic heart failure subgroups. The positive predictive value varied depending on the population of patients studied (p < 0.0001). CONCLUSIONS Microvolt T-wave alternans testing has significant value for the prediction of ventricular tachyarrhythmic events; however, there are significant limitations to its use. The predictive value of MTWA varies significantly depending on the population studied. Careful standardization is needed for what constitutes abnormal MTWA. The incremental prognostic value of MTWA when used with other methods of risk stratification is unclear.
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Affiliation(s)
- Anil K Gehi
- Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Al-Khatib SM, Sanders GD, Mark DB, Lee KL, Bardy GH, Bigger JT, Buxton AE, Connolly S, Kadish A, Moss A, Feldman AM, Ellenbogen KA, Singh S, Califf RM. Implantable cardioverter defibrillators and cardiac resynchronization therapy in patients with left ventricular dysfunction: randomized trial evidence through 2004. Am Heart J 2005; 149:1020-34. [PMID: 15976783 DOI: 10.1016/j.ahj.2005.02.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Although many studies have shown that implantable cardioverter defibrillator (ICD) therapy improves the survival of patients with significant left ventricular dysfunction, the magnitude of effectiveness of ICD therapy in clinically defined subgroups remains uncertain. Similarly, although studies have shown an improvement in patients' hemodynamics and quality of life with cardiac resynchronization therapy (CRT), there is a continuing uncertainty about the effect of CRT on patients' survival and the magnitude of improvement in quality of life with this therapy. On August 24, 2004, an ad hoc group of experts representing clinical cardiovascular medicine, biostatistics, economics, and health policy were joined by representatives of the Food and Drug Administration, Centers for Medicare and Medicaid Services (Baltimore, Md), Agency for Healthcare Research and Quality (Rockville, Md), and the device industry for a 1-day round table to review the available clinical trial evidence on the effect of ICD therapy in the primary prevention of sudden cardiac death and the effect of CRT in patients with congestive heart failure. The meeting was organized by the Duke Clinical Research Institute, Durham, NC, and funded in part by the Agency for Healthcare Research and Quality. This document summarizes the evidence reviewed at that meeting and the discussions of that evidence.
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Verrier RL, Nearing BD, Kwaku KF. Noninvasive sudden death risk stratification by ambulatory ECG-based T-wave alternans analysis: evidence and methodological guidelines. Ann Noninvasive Electrocardiol 2005; 10:110-20. [PMID: 15649246 PMCID: PMC6931922 DOI: 10.1111/j.1542-474x.2005.10103.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Extensive experimental and clinical evidence supports the utility of T-wave alternans (TWA) as a marker of risk for ventricular fibrillation. This entity appears to reflect the fundamental arrhythmogenic property of enhanced dispersion of repolarization. This relationship probably accounts for its relative ubiquity in patients with diverse types of cardiac disease, as has been recognized with the development of analytical tools. A basic premise of this review is that ambulatory ECG monitoring of TWA as patients experience the provocative stimuli of daily activities can expose latent electrical instability in individuals at heightened risk for arrhythmias. We will discuss the literature that supports this concept and summarize the current state of knowledge regarding the use of routine ambulatory ECGs to evaluate TWA for arrhythmia risk stratification. The dynamic, nonspectral modified moving average analysis method for assessing TWA, which is compatible with ambulatory ECG monitoring, is described along with methodological guidelines for its implementation. Finally, the rationale for combined monitoring of autonomic markers along with TWA will be presented.
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Affiliation(s)
- Richard L Verrier
- Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Furlanello F, Galanti G, Manetti P, Capalbo A, Pucci N, Michelucci A, Marangoni D, Terrasi F, Pettinati G, Cappato R. Microvolt T-wave alternans as predictor of electrophysiological testing results in professional competitive athletes. Ann Noninvasive Electrocardiol 2004; 9:201-6. [PMID: 15245334 PMCID: PMC6932000 DOI: 10.1111/j.1542-474x.2004.93543.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Several studies have confirmed the equivalence of the microvolt T-wave alternans (mTWA) and the electrophysiology (EPS) tests in cardiac disease. No data are available in populations of competitive athletes with arrhythmias that might jeopardize the pursuit of their professional career. METHODS We prospectively studied 100 trained competitive athletes, including elite types (72/100), (mean age +/- standard deviation: 26.1 +/- 4.5 years). Forty-eight of them were wholly normal (Group A, mean age: 24.5 +/- 8.5 years) and 52 of them had severe arrhythmias (Group B, mean age: 28.2 +/- 11.5 years) and were symptomatic in 85% of cases for prolonged palpitations and syncope, but lacked any overt structural heart disease at standardized cardiological screening. All athletes were evaluated with the microvolt T-wave alternans exercise-stress test, using the Heart Wave System with Microvolt Sensors. Group B underwent EPS to evaluate inducibility to sustained ventricular tachycardia (VT) during programmed electrical stimulation. RESULTS In Group A, the mTWA outcome was determinate in 45 subjects (94%) and indeterminate in 3 (6%). No symptomatic event was reported in a follow-up of 36.1 months. In Group B, the mTWA test was positive in 7 symptomatic subjects (15%), indeterminate in 3 (7%), and negative for the remaining 42 subjects (76%). Forty-one of 42 negative mTWA subjects were also negative in the EPS test, without any syncope or sustained VT during 25.3 months of follow-up. In the positive mTWA test subjects, 5 (72%) were positive for inducibility of rapid sustained monomorphic VT in EPS, 1 was positive for severe sustained atrial tachyarrhythmias, and 1 refused EPS. We were able to pronounce a correct diagnosis of lymphocytic myocarditis for only 1 mTWA and EPS-positive subject. For the other 4 positive patients with arrhythmogenic micropathology, severe arrhythmic events were revealed in the follow-up and aggressive hybrid treatment was necessary. CONCLUSION Microvolt-TWA study seems to be a useful, noninvasive, and feasible tool for evaluating arrhythmic risk in the athletic population. The mTWA test showed a high negative predictive value, using both EPS and the follow-up observation for severe arrhythmic cardiac events as an endpoint. The positive predictive value was present in a limited number of cases that were, however, subjects with a high risk of sudden arrhythmic death.
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Affiliation(s)
- Francesco Furlanello
- Department of Clinical Arrhythmia and Electrophysiology, San Donato Milanese Hospital, Milano, Italy.
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Armoundas AA, Albert CM, Cohen RJ, Mela T. Utility of Implantable Cardioverter Defibrillator Electrograms to Estimate Repolarization Alternans Preceding a Tachyarrhythmic Event. J Cardiovasc Electrophysiol 2004; 15:594-7. [PMID: 15149432 DOI: 10.1046/j.1540-8167.2004.03411.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Electrical alternans is a pattern of variation in the shape of the ECG waveform that appears on an every-other-beat basis. In humans, alternation in ventricular repolarization, namely, repolarization alternans, has been associated with increased vulnerability to ventricular tachycardia/ventricular fibrillation and sudden cardiac death. This study investigates the utility of implantable cardioverter defibrillator electrograms to estimate repolarization alternans preceding a tachyarrhythmic event. It is demonstrated that microvolt-level repolarization alternans is present prior to an arrhythmic event, and one can record low-amplitude-noise signals that can be used to obtain reliable estimates of repolarization alternans. This study eventually may lead to new methods that would prevent the onset of malignant tachyarrhythmias.
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Affiliation(s)
- Antonis A Armoundas
- Division of Molecular Cardiobiology, Johns Hopkins University, Baltimore, Maryland, USA.
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Abstract
Sudden cardiac death (SCD) is a leading cause of cardiovascular mortality. Therefore, identifying patients at highest risk for SCD is crucial. Conventional noninvasive markers of SCD are inadequate because of low positive predictive value. The presence of visible T-wave alternans (TWA) on electrocardiogram often predicts the occurrence of lethal ventricular arrhythmias. Signal processing methods have made it possible to detect microvolt-level and visually inapparent TWA on electrocardiogram. TWA is caused by underlying regional inhomogeneities of ventricular repolarization, which predispose patients to have ventricular arrhythmias. Microvolt TWA provoked either by atrial pacing, pharmacological stress, or exercise is a promising marker of arrhythmia vulnerability. Several large trials have shown TWA to be comparable or superior to other noninvasive markers and electrophysiologic study in the prediction of SCD. The patient populations in these trials include post myocardial infarction, both ischemic and nonischemic heart failure, and suspected arrhythmias. Prospective trials regarding benefits of implantation of cardioverter-defibrillator therapy based on TWA results are ongoing.
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Affiliation(s)
- Quan Pham
- Department of Medicine, The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109-1998, USA
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Steinbigler P, Haberl R, Steinbeck G. T wave spectral variance for noninvasive identification of patients with idiopathic dilated cardiomyopathy prone to ventricular fibrillation even in the presence of bundle branch block or atrial fibrillation. Pacing Clin Electrophysiol 2004; 27:156-65. [PMID: 14764165 DOI: 10.1111/j.1540-8159.2004.00405.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Conventional methods using Holter ECG recordings for noninvasive risk stratification are limited in patients with idiopathic dilated cardiomyopathy (IDC) prone to ventricular fibrillation (VF) having atrial fibrillation (AF) or bundle branch block (BBB). We therefore investigated, whether spectral assessment of beat-to-beat alternations of repolarization is associated with VF in these patients. Twenty-four-hour Holter ECG recordings in 462 patients with IDC were used. The VF group comprised of 64 consecutive patients who survived cardiac arrest, the no VF group consisted of 398 consecutive patients without a history of malignant ventricular arrhythmia. One hundred patients with ischemic cardiomyopathy (ICM) served as a control group. In each patient, 1,024 consecutive T waves were aligned using cross correlation methods. Two-dimensional Fourier transform (2D FFT) used the data matrix of 1,024 consecutive 200-ms segments centered to the T wave peak. Power spectra of the 2D FFT revealed the frequency content of the T wave in the first dimension and the periodicity of this frequency content in the second dimension. The ratio between periodic frequency contents and the sum of nonperiodic and periodic frequency contents between 0.5 and 50 Hz is equal to the T wave spectral variance (TWSV) index. Thus, TWSV index = 0 would mean that all 1,024 T waves are identical and TWSV index = 1 would mean that the 1,024 T waves are totally variable. The TWSV index was significantly higher in the VF group (0.93 +/- 0.14) than in the no VF group (0.53 +/- 0.13, P < 0.01). The best cutoff between the VF and the no VF group was achieved by using a TWSV index of 0.75 (sensitivity = 89%, specificity = 78%). No significant differences were observed between patients with and without AF or with and without BBB, and between patients with IDC and ICM. Even in the presence of BBB or AF spectral assessment of T wave alternations by TWSV index using 2D FFT in Holter ECG recordings, allows the identification of patients with IDC at risk for VF.
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Molon G, Marangoni D, Barbieri E. Spontaneous ventricular tachycardia and fibrillation in a patient with a positive microvolt T wave alternans test and negative electrophysiological study. Pacing Clin Electrophysiol 2004; 27:120-2. [PMID: 14720169 DOI: 10.1111/j.1540-8159.2004.00399.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This report describes a patient with a previous myocardial infarction who presented with syncope. The patient had a positive microvolt T wave alternans test, a negative electrophysiological study, and a normal heart rate variability. In hospital, the patient had episodes of ventricular tachycardia and fibrillation. An implantable cardioverter defibrillator was implanted and during the following week it discharged appropriately.
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Affiliation(s)
- Giulio Molon
- Department of Cardiology, Sacro Cuore Hospital, Verona, Italy.
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Abstract
Few data are available about the prognostic role of T wave alternans in patients with congestive heart failure. To assess the ability of T wave alternans, used alone or in combination with other risk markers, to predict cardiac death in decompensated patients, we enrolled 46 patients, mean age 59+/-9, males 89%, ischemic etiology 61%, NYHA class III 35%, left ventricular ejection fraction 29+/-7%. After 1.6 years follow-up, seven patients died from cardiac death (16%), non-sudden in six (86%) and sudden in one (14%). T wave alternans was positive in 24 (52%), negative in 13 (28%), indeterminate in nine patients (20%). T wave alternans was positive in all patients with events (100%) but only in 16 of 37 patients without (41%) (P=0.02). Other predictors of cardiac death were O(2) consumption at the peak of exercise (P=0.03), standard deviation of all NN intervals (P=0.05) and Wedge pressure (P=0.03). When receiver operator characteristics curves were calculated, the highest area (0.73) was found for O(2) consumption at the peak of exercise considering the single variables and for O(2) consumption at the peak of exercise plus T wave alternans (0.79) for combination of them; the comparison of the two receiver operator characteristics curves did not reach statistical difference (P=0.5). In conclusion, this is the first study reporting that T wave alternans can predict cardiac death, with a marginal additional prognostic power when used in combination with measurement of O(2) consumption at the peak of exercise.
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Affiliation(s)
- Simona Sarzi Braga
- IRCCS Fondazione Salvatore Maugeri, Divisione di Cardiologia, Istituto Scientifico di Tradate, Via Roncaccio 16 I-21049, Tradate (VA), Italy.
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Hohnloser SH, Klingenheben T, Bloomfield D, Dabbous O, Cohen RJ. Usefulness of microvolt T-wave alternans for prediction of ventricular tachyarrhythmic events in patients with dilated cardiomyopathy: results from a prospective observational study. J Am Coll Cardiol 2003; 41:2220-4. [PMID: 12821251 DOI: 10.1016/s0735-1097(03)00467-4] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVES This study was designed to evaluate the ability of microvolt-level T-wave alternans (MTWA) to identify prospectively patients with idiopathic dilated cardiomyopathy (DCM) at risk of ventricular tachyarrhythmic events and to compare its predictive accuracy with that of conventional risk stratifiers. BACKGROUND Patients with DCM are at increased risk of sudden death from ventricular tachyarrhythmias. At present, there are no established methods of assessing this risk. METHODS A total of 137 patients with DCM underwent risk stratification through assessment of MTWA, left ventricular ejection fraction, baroreflex sensitivity (BRS), heart rate variability, presence of nonsustained ventricular tachycardia (VT), signal-averaged electrocardiogram, and presence of intraventricular conduction defect. The study end point was either sudden death, resuscitated ventricular fibrillation, or documented hemodynamically unstable VT. RESULTS During an average follow-up of 14 +/- 6 months, MTWA and BRS were significant univariate predictors of ventricular tachyarrhythmic events (p < 0.035 and p < 0.015, respectively). Multivariate Cox regression analysis revealed that only MTWA was a significant predictor. CONCLUSIONS Microvolt-level T-wave alternans is a powerful independent predictor of ventricular tachyarrhythmic events in patients with DCM.
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Abstract
We review the contemporary understanding of the pathophysiology of repolarization alternans and present a perspective on the use of T-wave alternans (TWA) as a risk stratification marker of malignant ventricular arrhythmias. Several studies have demonstrated a high correlation of susceptibility to ventricular arrhythmias and sudden cardiac death with the existence of TWA. We describe a number of cellular and molecular alterations in the diseased heart that may provide a link between electrical and mechanical alternans and arrhythmia susceptibility. Repolarization alternans is likely the result of distinct and diverse cellular and molecular alterations that are associated with exaggerated regional repolarization heterogeneity, which renders the heart susceptible to malignant arrhythmias.
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Affiliation(s)
- Antonis A Armoundas
- Division of Molecular Cardiobiology, Johns Hopkins University, Ross 844, 720 Rutland Avenue, Baltimore, MD 21205, USA.
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Kitamura H, Ohnishi Y, Okajima K, Ishida A, Galeano E, Adachi K, Yokoyama M. Onset heart rate of microvolt-level T-wave alternans provides clinical and prognostic value in nonischemic dilated cardiomyopathy. J Am Coll Cardiol 2002; 39:295-300. [PMID: 11788222 DOI: 10.1016/s0735-1097(01)01718-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES This study was designed to determine the prognostic value of onset heart rate (OHR) in T-wave alternans (TWA) in patients with nonischemic dilated cardiomyopathy (DCM). BACKGROUND One of the current major issues in DCM is to prevent sudden cardiac death (SCD). However, the value of the OHR of TWA as a prognostic indicator in DCM remains to be elucidated. METHODS We prospectively investigated 104 patients with DCM undergoing TWA testing. The end point of this study was defined as SCD, documented sustained ventricular tachycardia/ventricular fibrillation. Relations between clinical parameters and subsequent outcome were evaluated. RESULTS Forty-six patients presenting with TWA were assigned to one of the following two subgroups according to OHR for TWA of < or = 100 beats/min: group A (n = 24) with OHR < or = 100 beats/min and group B (n = 22) with 100 < OHR < or = 110 beats/min. T-wave alternans was negative in 37 patients (group C) and indeterminate in 21 patients. The follow-up result comprised 83 patients with determined TWA. During a follow-up duration of 21 +/- 14 months, there was a total of 12 arrhythmic events, nine of which included three SCDs in group A, two in group B and one in group C. The forward stepwise multivariate Cox hazard analysis revealed that TWA with an OHR < or = 100 beats/min and left ventricular ejection fraction were independent predictors of these arrhythmic events (p = 0.0001 and p = 0.0152, respectively). CONCLUSIONS The OHR of TWA is of additional prognostic value in DCM.
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Affiliation(s)
- Hidetsuna Kitamura
- Division of Cardiovascular and Respiratory Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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Affiliation(s)
- N El-Sherif
- Cardiology Division, Department of Medicine, Box 1199, SUNY-Downstate Medical Center, Brooklyn, NY 11203, USA.
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Francis D, Lane R, Mayet J, Foale RA, Thom S, Peters NS. Microvolt T wave alternans in patients with hypertension and left ventricular hypertrophy. J Hum Hypertens 2001; 15 Suppl 1:S95-6. [PMID: 11685922 DOI: 10.1038/sj.jhh.1001254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- D Francis
- St Mary's Hospital and Imperial College School of Medicine, London, UK
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Abstract
PURPOSE AND DATA IDENTIFICATION: One of the main clinical problems of patients with arterial hypertension is the presence of arrhythmias, especially if left ventricular hypertrophy exists. Recent results from our group and all data available via Med-Line-search have been analysed. The analysis was focused on atrial and ventricular arrhythmias and arrhythmic risk prediction, using non-invasive markers. RESULTS OF ANALYSIS AND CONCLUSION: Arterial hypertension is a major cause of non-rheumatic atrial fibrillation and other supraventricular arrhythmias. The prevalence of ventricular arrhythmias is increased in hypertensive patients without left ventricular hypertrophy, compared to normotensives. If left ventricular hypertrophy is present, the risk for ventricular tachycardias is quadrupled. The presence of left ventricular hypertrophy is associated with an increase in all-cause mortality by a factor of seven in men and nine in women. In particular, patients with hypertrophy, increased rate of ventricular extrasystoles up to non-sustained ventricular tachycardia and ST-depression in long-term ECG are threatened by sudden cardiac death. At present, it is not possible to safely identify patients with increased risk. Regression of hypertrophy exists along with a decreased rate of ventricular extrasystoles. We hypothesize that by the regression of hypertrophy, the prevalence of sustained ventricular tachycardia decreases and therefore the prognosis of those patients can be improved, although controlled studies are not yet available.
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Affiliation(s)
- M G Hennersdorf
- Department of Cardiology, Pneumology and Angiology, Medical Clinic and Policlinic B, Heinrich-Heine-University, Duesseldorf, Germany.
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