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Antunes MO, Arteaga-Fernandez E, Samesima N, Pereira HG, Matsumoto AY, Verrier RL, Pastore CA, Mady C. Prognostic Evaluation of Microvolt T-Wave Alternans in Hypertrophic Cardiomyopathy: 9-year Clinical Follow-up. Arq Bras Cardiol 2023; 120:e20220833. [PMID: 37672406 PMCID: PMC10519242 DOI: 10.36660/abc.20220833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/25/2023] [Accepted: 06/14/2023] [Indexed: 09/08/2023] Open
Abstract
BACKGROUND Sudden cardiac death (SCD) resulting from ventricular arrhythmia is the main complication of hypertrophic cardiomyopathy (HCM). Microvolt T-wave alternans (MTWA) is associated with the occurrence of ventricular arrhythmias in several heart diseases, but its role in HCM remains uncertain. OBJECTIVE To evaluate the association of MTWA with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients in a long-term follow-up. METHODS Patients diagnosed with HCM and NYHA functional class I-II were consecutively selected. At the beginning of the follow-up, the participants performed the MTWA evaluation using the modified moving average during the stress test. The results were classified as altered or normal. The composite endpoint of SCD, ventricular fibrillation, sustained ventricular tachycardia (SVT) or appropriate implantable cardiac defibrillation (ICD) therapy was assessed. The level of significance was set at 5%. RESULTS A total of 132 patients (mean age of 39.5 ± 12.6 years) were recruited and followed for a mean of 9.5 years. The MTWA test was altered in 74 (56%) participants and normal in 58 (44%). Nine events (6.8%) occurred during the follow-up, with a prevalence of 1.0%/year - six SCDs, two appropriate ICD shocks and one episode of (SVT). Altered MTWA was associated with non-sustained ventricular tachycardia on Holter (p = 0.016), septal thickness ≥30 mm (p < 0.001) and inadequate blood pressure response to effort (p = 0.046). Five patients with altered MTWA (7%) and four patients with normal MTWA (7%) had the primary outcome [OR = 0.85 (95% CI: 0.21 - 3.35, p=0.83)]. Kaplan-Meir event curves showed no differences between normal and altered MTWA. CONCLUSION Altered MTWA was not associated with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients, and the low rate of these events during long-term follow-up suggests the good prognosis of this heart disease.
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Affiliation(s)
- Murillo Oliveira Antunes
- Universidade de São PauloFaculdade de MedicinaHospital das ClínicasSão PauloSPBrasilInstituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP – Brasil
- Universidade São FranciscoBragança PaulistaSPBrasilUniversidade São Francisco, Bragança Paulista, SP – Brasil
| | - Edmundo Arteaga-Fernandez
- Universidade de São PauloFaculdade de MedicinaHospital das ClínicasSão PauloSPBrasilInstituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP – Brasil
| | - Nelson Samesima
- Universidade de São PauloFaculdade de MedicinaHospital das ClínicasSão PauloSPBrasilInstituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP – Brasil
| | - Horácio Gomes Pereira
- Universidade de São PauloFaculdade de MedicinaHospital das ClínicasSão PauloSPBrasilInstituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP – Brasil
| | | | - Richard L. Verrier
- Beth Israel Deaconess Medical CenterBostonEUABeth Israel Deaconess Medical Center, Boston – EUA
| | - Carlos Alberto Pastore
- Universidade de São PauloFaculdade de MedicinaHospital das ClínicasSão PauloSPBrasilInstituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP – Brasil
| | - Charles Mady
- Universidade de São PauloFaculdade de MedicinaHospital das ClínicasSão PauloSPBrasilInstituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP – Brasil
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Pereira Filho HG, Samesima N, Madaloso BA, de Oliveira Tobias NMM, Facin M, Pastore CA. Modified moving average methodology applied to the treadmill stress testing analysis of microvolt T-wave alternans. Sci Rep 2022; 12:22454. [PMID: 36575194 PMCID: PMC9794681 DOI: 10.1038/s41598-022-26535-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 12/15/2022] [Indexed: 12/28/2022] Open
Abstract
Sudden cardiac death is impactful. There has been an increase in the search for tools capable of identifying individuals who are most susceptible, such as the microvolt T-wave alternans. This study aims to analyze the applicability of the modified moving average methodology to obtain the microvolt T-wave alternans using treadmill specific protocols. Medical records of patients during the period August 2006-December 2014 were retrospectively analyzed. Five hundred and thirty nine exams were then included, divided into groups according to the protocol and updating factor used: Ellestad factor 8 or 32, Naughton factor 8 or 32. The topics for analysis were the alternans behavior, noise and confirmation according to the groups of leads analyzed (frontal, transversal and orthogonal planes). The greater microvolt T-wave alternans was found during the stress phase in most of the tests. Group Naughton 8 presented lower noise in this phase for the transverse and orthogonal planes (p = 0.0082 and p < 0.0001), with greater confirmation of frontal and orthogonal planes in comparison with group Ellestad 8 (p = 0.0002 and 0.0008). The results indicate the viability of simultaneous performance of the stress test and measurement of the T wave alternans with Naughton protocol with 1/8 updating factor.
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Affiliation(s)
- Horacio Gomes Pereira Filho
- grid.11899.380000 0004 1937 0722Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Unidade de Eletrocardiografia, Sao Paulo, SP 05403-900 Brazil
| | - Nelson Samesima
- grid.11899.380000 0004 1937 0722Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Unidade de Eletrocardiografia, Sao Paulo, SP 05403-900 Brazil
| | - Bruna Affonso Madaloso
- grid.11899.380000 0004 1937 0722Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Unidade de Eletrocardiografia, Sao Paulo, SP 05403-900 Brazil
| | - Nancy Maria Martins de Oliveira Tobias
- grid.11899.380000 0004 1937 0722Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Unidade de Eletrocardiografia, Sao Paulo, SP 05403-900 Brazil
| | - Mirella Facin
- grid.11899.380000 0004 1937 0722Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Unidade de Eletrocardiografia, Sao Paulo, SP 05403-900 Brazil
| | - Carlos Alberto Pastore
- grid.11899.380000 0004 1937 0722Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Unidade de Eletrocardiografia, Sao Paulo, SP 05403-900 Brazil
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Hashimoto K, Harada N, Kasamaki Y. Reference values for a novel ambulatory-based frequency domain T-wave alternans in subjects without structural heart disease. J Cardiol 2020; 76:506-513. [PMID: 32624298 DOI: 10.1016/j.jjcc.2020.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 04/12/2020] [Accepted: 05/17/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Conventional frequency domain T wave alternans (FD-TWA) is a noninvasive risk stratification marker for identifying arrhythmic sudden cardiac death, but the conventional FD-TWA device that was considered the gold standard device has been discontinued commercially. Recently, a newly developed ambulatory electrocardiogram (AECG) device that can detect FD-TWA continuously for 24 hours is available in clinical settings. However, information on the normal values using the novel AECG-based frequency domain TWA (FD-TWA) is lacking. METHODS FD-TWA for AECG was examined in 312 subjects without heart disease (Sb-wHD) (range 20-89 years, 146 men) and 30 heart disease patients (HD-P) (mean age 57±17 years, 24 men). The maximum FD-TWA amplitude over 24 hours was measured with manual editing. The upper limit of local noise levels for measurement of FD-TWA was set to both <10 μV and <20 μV (acceptable noise level <10 μV and <20 μV). RESULTS The reference values (95th percentiles) of FD-TWA in Sb-wHD were 19.9 μV for the acceptable noise level <10 μV and 23.6 μV for the acceptable noise level <20 μV. The 75th percentile of FD-TWA amplitude in HD-P was 19.5 µV at an acceptable noise level <10 µV and 21.5 µV at an acceptable noise level <20 µV. FD-TWA amplitude without heart disease was significantly affected by heart rate when the maximum FD-TWA was measured (β = 0.274 p < 0.001 for the acceptable noise level <10 μV; β = 0.263, p < 0.001 for the acceptable noise level <20 μV) and age (β = 0.204, p = 0.004 for the acceptable noise level <10 μV; β = 0.149, p = 0.034 for the acceptable noise level <20 μV). CONCLUSIONS In the present study, the reference values for a novel FD-TWA in Sb-wHD and the distribution of TWA values in HD-P were established. In future research, the cut-off values of FD-TWA in HD-P will need to be examined.
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Affiliation(s)
- Kenichi Hashimoto
- Department of General Medicine, National Defense Medical College, Tokorozawa, Saitama, Japan.
| | - Naomi Harada
- Division of General Medicine, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Yuji Kasamaki
- Department of Community Medicine, Kanazawa Medical University Himi Municipal Hospital, Himi, Toyama, Japan
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Welsh AJ, Delgado C, Lee-Trimble C, Kaboudian A, Fenton FH. Simulating waves, chaos and synchronization with a microcontroller. CHAOS (WOODBURY, N.Y.) 2019; 29:123104. [PMID: 31893636 PMCID: PMC7195869 DOI: 10.1063/1.5094351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 10/22/2019] [Indexed: 05/12/2023]
Abstract
The spatiotemporal dynamics of complex systems have been studied traditionally and visualized numerically using high-end computers. However, due to advances in microcontrollers, it is now possible to run what once were considered large-scale simulations using a very small and inexpensive single integrated circuit that can furthermore send and receive information to and from the outside world in real time. In this paper, we show how microcontrollers can be used to perform simulations of nonlinear ordinary differential equations with spatial coupling and to visualize their dynamics using arrays of light-emitting diodes and/or touchscreens. We demonstrate these abilities using three different models: two reaction-diffusion models (one neural and one cardiac) and a generic model of network oscillators. These models are commonly used to simulate various phenomena in biophysical systems, including bifurcations, waves, chaos, and synchronization. We also demonstrate how simple it is to integrate real-time user interaction with the simulations by showing examples with a light sensor, touchscreen, and web browser.
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Affiliation(s)
- Andrea J Welsh
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Cristian Delgado
- Facultad de Ciencias, Universidad Nacional Autònoma de México, Distrito Federal 04510, Mexico
| | | | - Abouzar Kaboudian
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Flavio H Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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Arsenos P, Gatzoulis KA, Dilaveris P, Sideris S, Tousoulis D. T wave alternans extracted from 30-minute short resting Holter ECG recordings predicts mortality in heart failure. J Electrocardiol 2018; 51:588-591. [PMID: 29996995 DOI: 10.1016/j.jelectrocard.2018.03.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/12/2018] [Accepted: 03/24/2018] [Indexed: 11/15/2022]
Abstract
BACKGROUND We extracted T Wave Alternans (TWA) from a 30 minute Short Resting Holter ECG (SRH ECG) in the supine position, as a Total Mortality (TM) predictor in Heart Failure (HF). METHODS Signals from 146 HF patients (LVEF = 33 ± 10%), were analyzed with Modified Moving Average method. After 42.1 months, 26 patients died. RESULTS (Deceased vs Living group): TWA:31 ± 18 μV vs 25 ± 13 μV(p = 0.05), LVEF:32 ± 10% vs 34 ± 9% (p = 0.5), Heart Rate:73 ± 11 bpm vs 69 ± 12 bpm (p = 0.2), SDNN/HRV:45 ± 42 ms vs 41 ± 29 ms (p = 0.4), QRS:123 ± 26 ms vs 119 ± 29 ms (p = 0.5).Cox regression model adjusted for TWA, LVEF and QRS, revealed that the TWA was an independent TM predictor (H.R.: 1.022, 95% C.I.: 0.999-1.046, p = 0.05).The TWA ≥ 42 μV demonstrated HR: 2.521, (95% C.I.: 0.982-6.472, p = 0.05). CONCLUSIONS In severely affected HF patients, TWA from a SRH ECG may be present even during slow resting heart rates and proved to be an important and independent TM predictor. The SRH ECG recording is an efficient and fast method for mortality risk evaluation in HF patients.
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Affiliation(s)
- Petros Arsenos
- First Department of Cardiology and Electrophysiology Laboratory, Hippokration General Hospital, National and Kapodistrian, University of Athens School of Medicine, Athens, Greece; Arsenos Heart and Biosignals Lab., Avlonas, Attica, Greece.
| | - Konstantinos A Gatzoulis
- First Department of Cardiology and Electrophysiology Laboratory, Hippokration General Hospital, National and Kapodistrian, University of Athens School of Medicine, Athens, Greece
| | - Polychronis Dilaveris
- First Department of Cardiology and Electrophysiology Laboratory, Hippokration General Hospital, National and Kapodistrian, University of Athens School of Medicine, Athens, Greece
| | - Skevos Sideris
- State Department of Cardiology, Hippokration General Hospital, Athens, Greece
| | - Dimitrios Tousoulis
- First Department of Cardiology and Electrophysiology Laboratory, Hippokration General Hospital, National and Kapodistrian, University of Athens School of Medicine, Athens, Greece
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Abstract
The Centers for Diseases Control and Prevention estimates that 5.7 million adults in the United States suffer from heart failure and 1 in 9 deaths in 2009 cited heart failure as a contributing cause. Almost 50% of patients who are diagnosed with heart failure die within 5 years of diagnosis. Cardiovascular disease is a public health burden. The prognosis of patients with heart failure has improved significantly. However, the risk for death remains high. Managing sudden death risk and intervening appropriately with primary or secondary prevention strategies are of paramount importance.
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Affiliation(s)
- Basil Saour
- Department of Internal Medicine, Division of Cardiology, Northwestern University, Feinberg School of Medicine, 420 E Superior Street, Chicago, IL 60611, USA
| | - Bryan Smith
- Department of Internal Medicine, Division of Cardiology, Northwestern University, Feinberg School of Medicine, 420 E Superior Street, Chicago, IL 60611, USA
| | - Clyde W Yancy
- Department of Internal Medicine, Division of Cardiology, Northwestern University, Feinberg School of Medicine, 420 E Superior Street, Chicago, IL 60611, USA.
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The Application of Ambulatory Electrocardiographically-Based T-Wave Alternans in Patients with Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy. Can J Cardiol 2016; 32:1355.e15-1355.e22. [DOI: 10.1016/j.cjca.2016.01.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 11/18/2022] Open
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Exercise-induced quantitative microvolt T-wave alternans in hypertrophic cardiomyopathy. J Electrocardiol 2016; 50:184-190. [PMID: 27916321 DOI: 10.1016/j.jelectrocard.2016.10.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND/PURPOSE Patients with hypertrophic cardiomyopathy (HCM) have elevated risk for sudden cardiac death (SCD). Our study aimed to quantitatively characterize microvolt T-wave alternans (TWA), a potential arrhythmia risk stratification tool, in this HCM patient population. METHODS TWA was analyzed with the quantitative modified moving average (MMA) in 132 HCM patients undergoing treadmill exercise testing, grouped according to Maron score risk factors as high-risk (H-Risk, n=67,), or low-risk (L-Risk, n=65, without these risk factors). RESULTS TWA levels were much higher for the H-Risk than for the L-Risk group (101.40±75.61 vs. 54.35±46.26μV; p<0.0001). A 53μV cut point, set by receiver operator characteristic (ROC), identified H-Risk patients (82% sensitivity, 69% specificity). CONCLUSIONS High TWA levels were found for hypertrophic cardiomyopathy patients. Abnormal TWA associated with major risk factors for SCD: non-sustained ventricular tachycardia on Holter (p=0.001), family history of SCD (p=0.006), septal thickness ≥30mm (p<0.001); and inadequate blood pressure response to effort (p=0.04).
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Zhen Z, Chen Y, Liu JH, Chan CWS, Yuen M, Lam KSL, Tse HF, Yiu KH. Increased T-wave alternans is associated with subclinical myocardial structural and functional abnormalities in patients with type 2 diabetes. J Cardiol 2016; 68:329-34. [DOI: 10.1016/j.jjcc.2015.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/09/2015] [Accepted: 10/13/2015] [Indexed: 10/22/2022]
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Burattini L, Man S, Fioretti S, Di Nardo F, Swenne CA. Heart Rate-Dependent Hysteresis of T-Wave Alternans in Primary Prevention ICD Patients. Ann Noninvasive Electrocardiol 2015; 21:460-9. [PMID: 26671620 DOI: 10.1111/anec.12330] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND T-wave alternans (TWA) is usually performed at accelerated heart rates (HR) during exercise, while recovery TWA is typically not analyzed. Consequently, it is still unknown if TWA shows a HR-dependent hysteresis or not. Thus, the aim of the present study was to investigate TWA dependency on HR during both the exercise and recovery phases of an ergometer test, and to evaluate if recovery TWA may contribute to identify subjects at increased risk of arrhythmic events. METHODS Our HR adaptive match filter was used to identify TWA from electrocardiographic recordings acquired during a bicycle ergometer test in 266 patients with implanted cardio-defibrillator. During the 4-year follow-up, 76 patients developed tachycardia or ventricular fibrillation (ICD_Cases) and 190 did not (ICD_Controls). RESULTS TWA was statistically lower during exercise than recovery for HRs between 75 and 110 bpm (16-21 μV vs 20-27 μV; P < 0.05), and reverse for HRs between 120 and 130 bpm (41-51 μV vs 28 μV; P < 0.05). ICD_Cases and ICD_Controls showed significantly different TWA at 80 bpm (20 μV vs 15 μV; P < 0.05) and 140 bpm (15 μV vs 22 μV; P < 0.05) during exercise, and at 90 bpm (38 μV vs 21 μV; P < 0.05) and 95 bpm (33-24 μV vs 28 μV; P < 0.05) during recovery. CONCLUSIONS TWA shows a HR-dependent hysteresis and there is a different behavior of TWA in ICD_Cases and ICD_Controls groups. Consequently, beside exercise TWA also recovery TWA may contribute to identify subjects at increased risk of arrhythmic events.
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Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Sumche Man
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Sandro Fioretti
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Francesco Di Nardo
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Cees A Swenne
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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Meste O, Janusek D, Karczmarewicz S, Przybylski A, Kania M, Maciag A, Maniewski R. Improved robust T-wave alternans detectors. Med Biol Eng Comput 2015; 53:361-70. [PMID: 25644059 DOI: 10.1007/s11517-015-1243-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 01/12/2015] [Indexed: 10/24/2022]
Abstract
New statistical and spectral detectors, the modified matched pairs t test, the extended spectral method and the modified spectral method, were proposed for T-wave alternans (TWA) detection gaining robustness according to trend and single-frequency interferences. They were compared to classic detectors such as matched pairs t test, unpaired t test, spectral method, generalized likelihood ratio test and estimated TWA amplitude within a simulation framework and applied to real data. The optimal detection threshold was selected by using a full Monte-Carlo simulation where signals, with and without alternans episodes, were corrupted by Gaussian noise with different power and single-frequency interferences with different tones. All the combinations of noise and frequency were selected and repeated 500 times in order to compute probability of detection ([Formula: see text]) and the false alarm probability ([Formula: see text]), providing ROC curves. The study group consisted of 50 patients with implantable cardioverter-defibrillator (age: [Formula: see text]; LVEF: [Formula: see text]), who were paced (ventricular pacing) at 100 bpm. Two-minute recordings were analyzed. The XYZ orthogonal lead system was used. The best performance was reached by using the modified matched pairs t test (in comparison with the spectral method and other reference methods).
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Affiliation(s)
- O Meste
- Laboratoire I3S UNS-CNRS UMR7172, Université de Nice-Sophia Antipolis, 2000 route des lucioles Les Algorithmes - bt. Euclide B, CS 40121, 06903, Sophia Antipolis Cedex, France,
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12
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Burattini L, Man S, Fioretti S, Di Nardo F, Swenne CA. Dependency of exercise-induced T-wave alternans predictive power for the occurrence of ventricular arrhythmias from heart rate. Ann Noninvasive Electrocardiol 2014; 20:345-54. [PMID: 25367434 DOI: 10.1111/anec.12224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND T-wave alternans (TWA) is a noninvasive index of risk for the occurrence of ventricular arrhythmias. It is known that TWA amplitude (TWAA) increases with heart rate (HR) but how the TWA predictive power varies with HR remains unknown. Thus, the aim of this study was to evaluate the dependency of exercise-induced TWA predictive power for the occurrence of ventricular arrhythmias from HR. METHODS TWA was identified using our HR adaptive match filter in exercise ECGs from 248 patients with implanted cardiac defibrillator (ICD), of which 72 developed ventricular tachycardia and/or fibrillation during the 4 year follow-up (ICD_Cases) and 176 did not (ICD_Controls). TWA predictive power was evaluated at HRs from 80 to 120 bpm by computing the area under the receiver operating characteristic curve (AUC) obtained using the maximum TWAA (maxTWAA) and the TWAA ratio (TWAAratio; i.e., the ratio between TWAA at a specific HR and at 80 bpm). RESULTS TWAA increased with HR. At 80 bpm maxTWAA was lower than at 120 bpm in both ICD_Cases (22 μV vs 41 μV; P < 10(-2) ) and ICD_ Controls (16 μV vs 36 μV; P < 10(-4) ). However, only at 80 bpm ICD_Cases showed significantly higher maxTWAA than ICD_Controls (AUC = 0.6486; P = 0.0080). TWAAratio was higher in ICD_Controls than ICD_Cases for all HR but 120 bpm, and its predictive power was maximum at 115 bpm (AUC = 0.6914; P < 0.05). CONCLUSIONS Exercise-induced TWA predictive power for the occurrence of ventricular arrhythmias, quantified using both maxTWAA and TWAAratio, was higher at low rather than at high HR.
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Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy.,B.M.E.D. Bio-Medical Engineering Development SRL, Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Sumche Man
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Francesco Di Nardo
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Cees A Swenne
- B.M.E.D. Bio-Medical Engineering Development SRL, Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
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Minkkinen M, Nieminen T, Verrier RL, Leino J, Lehtimäki T, Viik J, Lehtinen R, Nikus K, Kööbi T, Turjanmaa V, Kähönen M. Prognostic capacity of a clinically indicated exercise test for cardiovascular mortality is enhanced by combined analysis of exercise capacity, heart rate recovery and T-wave alternans. Eur J Prev Cardiol 2014; 22:1162-70. [DOI: 10.1177/2047487314557190] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 10/07/2014] [Indexed: 11/15/2022]
Affiliation(s)
- Mikko Minkkinen
- Department of Internal Medicine, Helsinki University Central Hospital, Finland
- Department of Clinical Physiology, Tampere University Hospital, Finland
| | - Tuomo Nieminen
- Department of Internal Medicine, University of Helsinki and South Karelia Central Hospital, Lappeenranta, Finland
| | - Richard L Verrier
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Johanna Leino
- Department of Clinical Physiology, Tampere University Hospital, Finland
- School of Medicine, University of Tampere, Finland
| | - Terho Lehtimäki
- School of Medicine, University of Tampere, Finland
- Department of Clinical Chemistry, Tampere University Hospital, Finland
| | - Jari Viik
- Department of Biomedical Engineering, Tampere University of Technology and BioMeditech, Tampere, Finland
| | | | - Kjell Nikus
- Department of Cardiology, Tampere University Hospital, Finland
| | - Tiit Kööbi
- Department of Clinical Physiology, Tampere University Hospital, Finland
- School of Medicine, University of Tampere, Finland
| | | | - Mika Kähönen
- Department of Clinical Physiology, Tampere University Hospital, Finland
- School of Medicine, University of Tampere, Finland
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14
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Deogire A, Hamde S. Effect of a multi-lead PCA approach on modified moving average method for T-wave alternans detection. J Med Eng Technol 2014; 38:396-401. [DOI: 10.3109/03091902.2014.960605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Kenttä T, Tulppo MP, Nearing BD, Karjalainen JJ, Hautala AJ, Kiviniemi AM, Huikuri HV, Verrier RL. Effects of exercise rehabilitation on cardiac electrical instability assessed by T-wave alternans during ambulatory electrocardiogram monitoring in coronary artery disease patients without and with diabetes mellitus. Am J Cardiol 2014; 114:832-7. [PMID: 25107578 DOI: 10.1016/j.amjcard.2014.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/25/2014] [Accepted: 06/25/2014] [Indexed: 10/25/2022]
Abstract
Effects of exercise rehabilitation on electrocardiographic markers of risk for sudden cardiac death have not been adequately studied. We examined effects of controlled exercise training on T-wave alternans (TWA) in 24-hour ambulatory electrocardiogram recordings in patients with stable coronary artery disease (CAD) without and with type 2 diabetes mellitus (DM). Consecutive patients with angiographically confirmed CAD were recruited to join the ARTEMIS (Innovation to Reduce Cardiovascular Complications of Diabetes at the Intersection) study. Exercise (n = 65) and control groups (n = 65) were matched on age, sex, DM, and previous myocardial infarction. Ambulatory electrocardiograms were recorded before and after a 2-year training period. TWA was assessed using time domain-modified moving average method by an investigator blinded to patients' clinical status. Average TWA values decreased in the rehabilitation group but not in control patients (rehabilitation [mean ± SEM]: 52.8 ± 1.7 μV vs 48.7 ± 1.5 μV, p <0.001; control: 53.7 ± 1.7 μV vs 54.3 ± 1.6 μV, p = 0.746). Changes in TWA differed between the groups (rehabilitation: -4.1 ± 1.2 μV vs controls: +0.6 ± 1.1 μV, p = 0.005). In CAD + DM patients, 50% (n = 9) of the 18 positive TWA cases were converted with exercise versus 10% (n = 2 of 20) of controls (p = 0.020). In CAD patients, 30% (n = 8 of 27) of positive TWA cases were converted with exercise versus 4% (n = 1 of 28) of controls (p = 0.012). In conclusion, this is the first report of the effectiveness of exercise rehabilitation to reduce TWA, a marker of sudden cardiac death risk, in patients with stable CAD.
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Yodogawa K, Shimizu W. Noninvasive risk stratification of lethal ventricular arrhythmias and sudden cardiac death after myocardial infarction. J Arrhythm 2014. [DOI: 10.1016/j.joa.2014.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Burattini L, Man S, Sweene CA. The power of exercise-induced T-wave alternans to predict ventricular arrhythmias in patients with implanted cardiac defibrillator. JOURNAL OF HEALTHCARE ENGINEERING 2013; 4:167-84. [PMID: 23778010 DOI: 10.1260/2040-2295.4.2.167] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The power of exercise-induced T-wave alternans (TWA) to predict the occurrence of ventricular arrhythmias was evaluated in 67 patients with an implanted cardiac defibrillator (ICD). During the 4-year follow-up, electrocardiographic (ECG) tracings were recorded in a bicycle ergometer test with increasing workload ranging from zero (NoWL) to the patient's maximal capacity (MaxWL). After the follow-up, patients were classified as either ICD_Cases (n = 29), if developed ventricular tachycardia/fibrillation, or ICD_Controls (n = 38). TWA was quantified using our heart-rate adaptive match filter. Compared to NoWL, MaxWL was characterized by faster heart rates and higher TWA in both ICD_Cases (12-18 μ V vs. 20-39 μ V; P < 0.05) and ICD_Controls (9-15 μ V vs. 20-32 μ V; P < 0.05). Still, TWA was able to discriminate the two ICD groups during NoWL (sensitivity = 59-83%, specificity = 53-84%) but not MaxWL (sensitivity = 55-69%, specificity = 39-74%). Thus, this retrospective observational case-control study suggests that TWA's predictive power for the occurrence of ventricular arrhythmias could increase at low heart rates.
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Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy.
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T wave alternans in experimental myocardial infarction: Time course and predictive value for the assessment of myocardial damage. J Electrocardiol 2013; 46:263-9. [DOI: 10.1016/j.jelectrocard.2013.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Indexed: 11/18/2022]
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Burattini L, Man S, Burattini R, Swenne CA. Comparison of standard versus orthogonal ECG leads for T-wave alternans identification. Ann Noninvasive Electrocardiol 2012; 17:130-40. [PMID: 22537331 DOI: 10.1111/j.1542-474x.2012.00490.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
T-wave alternans (TWA), an electrophysiologic phenomenon associated with ventricular arrhythmias, is usually detected from selected ECG leads. TWA amplitude measured in the 12-standard and the 3-orthogonal (vectorcardiographic) leads were compared here to identify which lead system yields a more adequate detection of TWA as a noninvasive marker for cardiac vulnerability to ventricular arrhythmias. Our adaptive match filter (AMF) was applied to exercise ECG tracings from 58 patients with an implanted cardiac defibrillator, 29 of which had ventricular tachycardia or fibrillation during follow-up (cases), while the remaining 29 were used as controls. Two kinds of TWA indexes were considered, the single-lead indexes, defined as the mean TWA amplitude over each lead (MTWAA), and lead-system indexes, defined as the mean and the maximum MTWAA values over the standard leads and over the orthogonal leads. Significantly (P < 0.05) higher TWA in the cases versus controls was identified only occasionally by the single-lead indexes (odds ratio: 1.0-9.9, sensitivity: 24-76%, specificity: 76-86%), and consistently by the lead-system indexes (odds ratio: 4.5-8.3, sensitivity: 57-72%, specificity: 76%). The latter indexes also showed a significant correlation (0.65-0.83) between standard and orthogonal leads. Hence, when using the AMF, TWA should be detected in all leads of a system to compute the lead-system indexes, which provide a more reliable TWA identification than single-lead indexes, and a better discrimination of patients at increased risk of cardiac instability. The standard and the orthogonal leads can be considered equivalent for TWA identification, so that TWA analysis can be limited to one-lead system.
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Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy.
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Kusha M, Masse S, Farid T, Urch B, Silverman F, Brook RD, Gold DR, Mangat I, Speck M, Nair K, Poku K, Meyer C, Mittleman MA, Wellenius GA, Nanthakumar K. Controlled exposure study of air pollution and T-wave alternans in volunteers without cardiovascular disease. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:1157-1161. [PMID: 22552907 PMCID: PMC3440072 DOI: 10.1289/ehp.1104171] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 05/02/2012] [Indexed: 05/31/2023]
Abstract
BACKGROUND Epidemiological studies have assessed T-wave alternans (TWA) as a possible mechanism of cardiac arrhythmias related to air pollution in high-risk subjects and have reported associations with increased TWA magnitude. OBJECTIVE In this controlled human exposure study, we assessed the impact of exposure to concentrated ambient particulate matter (CAP) and ozone (O3) on T-wave alternans in resting volunteers without preexisting cardiovascular disease. METHODS Seventeen participants without preexisting cardiovascular disease were randomized to filtered air (FA), CAP (150 μg/m3), O3 (120 ppb), or combined CAP + O3 exposures for 2 hr. Continuous electrocardiograms (ECGs) were recorded at rest and T-wave alternans (TWA) was computed by modified moving average analysis with QRS alignment for the artifact-free intervals of 20 beats along the V2 and V5 leads. Exposure-induced changes in the highest TWA magnitude (TWAMax) were estimated for the first and last 5 min of each exposure (TWAMax_Early and TWAMax_Late respectively). ΔTWAMax (Late-Early) were compared among exposure groups using analysis of variance. RESULTS Mean ± SD values for ΔTWAMax were -2.1 ± 0.4, -2.7 ± 1.1, -1.9 ± 1.5, and -1.2 ± 1.5 in FA, CAP, O3, and CAP + O3 exposure groups, respectively. No significant differences were observed between pollutant exposures and FA. CONCLUSION In our study of 17 volunteers who had no preexisting cardiovascular disease, we did not observe significant changes in T-wave alternans after 2-hr exposures to CAP, O3, or combined CAP + O3. This finding, however, does not preclude the possibility of pollution-related effects on TWA at elevated heart rates, such as during exercise, or the possibility of delayed responses.
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Affiliation(s)
- Marjan Kusha
- Division of Cardiology, Toronto General Hospital, Toronto, Ontario, Canada
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Koskela J, Kähönen M, Nieminen T, Lehtinen R, Viik J, Nikus K, Niemelä K, Kööbi T, Tobin MD, Samani NJ, Turjanmaa V, Pörsti I, Lehtimäki T. Allelic variant of NOS1AP effects on cardiac alternans of repolarization during exercise testing. Scandinavian Journal of Clinical and Laboratory Investigation 2011; 72:100-7. [PMID: 22133205 DOI: 10.3109/00365513.2011.638725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION A repolarization abnormality manifested as T-wave alternans (TWA) in electrocardiogram (ECG) predicts cardiovascular mortality. A common variant in the NOS1AP gene is associated with mortality and QT interval duration, possibly in a gender-specific manner, but data is lacking on potential association with TWA. This study tested association between rs10494366 in NOS1AP and both TWA and 4-year mortality. MATERIAL AND METHODS A total of 1963 Finnish Cardiovascular Study participants (36.6% female, 57.1 ± 13.0 years) were genotyped and their maximal TWA values were measured from continuous ECG recordings during clinical exercise test at rest, exercise and recovery. RESULTS We observed a significant gender-specific effect of NOS1AP genotype on TWA. In all subjects, there was no statistically significant difference between the three genotypes (TT, TG, GG) in the responses of TWA over the entire exercise test (time-by-genotype interaction p = 0.057). In women, after adjustment for age, coronary heart disease and β-blocker medication status, changes of TWA over different phases of exercise test were significantly associated with NOS1AP genotype (time-by-genotype interaction p = 0.001). In men, NOS1AP rs10494366 was not associated with TWA. During follow-up (mean 47 months), 113 patients died. NOS1AP rs10494366 was not a statistically significant predictor of mortality. CONCLUSION The NOSIAP variant rs10494366 influences TWA and TWA response during clinical exercise test in females. Gender-specific effects have also been previously reported for the influence of the variant on QT interval. If replicated, these findings should prompt studies to further elucidate the mechanisms underlying the gender differences in NOS1AP effects on repolarization.
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Affiliation(s)
- Jenni Koskela
- Department of Internal Medicine, Tampere University Hospital and School of Medicine at the University of Tampere, Finland.
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Verrier RL, Klingenheben T, Malik M, El-Sherif N, Exner DV, Hohnloser SH, Ikeda T, Martínez JP, Narayan SM, Nieminen T, Rosenbaum DS. Microvolt T-wave alternans physiological basis, methods of measurement, and clinical utility--consensus guideline by International Society for Holter and Noninvasive Electrocardiology. J Am Coll Cardiol 2011; 58:1309-24. [PMID: 21920259 DOI: 10.1016/j.jacc.2011.06.029] [Citation(s) in RCA: 286] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 06/10/2011] [Accepted: 06/13/2011] [Indexed: 10/17/2022]
Abstract
This consensus guideline was prepared on behalf of the International Society for Holter and Noninvasive Electrocardiology and is cosponsored by the Japanese Circulation Society, the Computers in Cardiology Working Group on e-Cardiology of the European Society of Cardiology, and the European Cardiac Arrhythmia Society. It discusses the electrocardiographic phenomenon of T-wave alternans (TWA) (i.e., a beat-to-beat alternation in the morphology and amplitude of the ST-segment or T-wave). This statement focuses on its physiological basis and measurement technologies and its clinical utility in stratifying risk for life-threatening ventricular arrhythmias. Signal processing techniques including the frequency-domain Spectral Method and the time-domain Modified Moving Average method have demonstrated the utility of TWA in arrhythmia risk stratification in prospective studies in >12,000 patients. The majority of exercise-based studies using both methods have reported high relative risks for cardiovascular mortality and for sudden cardiac death in patients with preserved as well as depressed left ventricular ejection fraction. Studies with ambulatory electrocardiogram-based TWA analysis with Modified Moving Average method have yielded significant predictive capacity. However, negative studies with the Spectral Method have also appeared, including 2 interventional studies in patients with implantable defibrillators. Meta-analyses have been performed to gain insights into this issue. Frontiers of TWA research include use in arrhythmia risk stratification of individuals with preserved ejection fraction, improvements in predictivity with quantitative analysis, and utility in guiding medical as well as device-based therapy. Overall, although TWA appears to be a useful marker of risk for arrhythmic and cardiovascular death, there is as yet no definitive evidence that it can guide therapy.
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Affiliation(s)
- Richard L Verrier
- Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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Monasterio V, Laguna P, Cygankiewicz I, Vázquez R, Bayés-Genís A, de Luna AB, Martínez JP. Average T-wave alternans activity in ambulatory ECG records predicts sudden cardiac death in patients with chronic heart failure. Heart Rhythm 2011; 9:383-9. [PMID: 22024149 DOI: 10.1016/j.hrthm.2011.10.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Accepted: 10/19/2011] [Indexed: 12/25/2022]
Abstract
BACKGROUND T-wave alternans (TWA) is a well-documented noninvasive electrocardiographic (ECG) method useful for identifying patients at risk for sudden cardiac death (SCD). OBJECTIVE The purpose of this study was to evaluate whether the long-term average TWA activity on Holter monitoring provides prognostic information in patients with chronic heart failure. METHODS Twenty-four-hour Holter ECGs from 650 ambulatory patients with mild-to-moderate chronic heart failure were analyzed in the study. Average TWA activity was measured by using a fully automated multilead technique, and 2 indices were proposed to quantify TWA: an index quantifying the average TWA activity in the whole recording (IAA), which was used to define a positive/negative TWA test, and an index quantifying the average TWA activity at heart rates between 80 and 90 beats/min (IAA(90)). RESULTS Patients were divided into TWA positive (TWA+) and TWA negative (TWA-) groups by setting a cut point of 3.7 μV for IAA, corresponding to the 75th percentile of the distribution of IAA in the population. After a median follow-up of 48 months, the survival rate was significantly higher in the TWA- group for cardiac death and SCD (p = .017 and p = .001, respectively). Multivariate Cox proportional hazards analysis revealed that both TWA+ and IAA(90) were associated with SCD with hazard rates of 2.29 (p = .004) and 1.07 per μV (p = .046), respectively. CONCLUSION The average TWA activity measured automatically from Holter ECGs predicted SCD in patients with mild-to-moderate chronic heart failure.
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Affiliation(s)
- Violeta Monasterio
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Aragon, Spain.
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Strzelczyk A, Adjei P, Scott CA, Bauer S, Rosenow F, Walker MC, Surges R. Postictal increase in T-wave alternans after generalized tonic-clonic seizures. Epilepsia 2011; 52:2112-7. [DOI: 10.1111/j.1528-1167.2011.03266.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yu H, Pi-Hua F, Yuan W, Xiao-Feng L, Jun L, Zhi L, Sen L, Zhang S. Prediction of sudden cardiac death in patients after acute myocardial infarction using T-wave alternans: a prospective study. J Electrocardiol 2011; 45:60-5. [PMID: 21920535 DOI: 10.1016/j.jelectrocard.2011.07.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Indexed: 01/28/2023]
Abstract
BACKGROUND AND PURPOSE We assessed the value of T-wave alternans (TWA) in prediction of sudden cardiac death (SCD) in patients with acute myocardial infarction (AMI). METHODS Consecutive patients (N = 227) were enrolled and were monitored with 24-hour ambulatory electrocardiogram within 1 to 15 days after AMI. T-wave alternans was identified by a modified moving average (MMA) algorithm computer software. The primary end point was SCD or lethal ventricular arrhythmia. We analyzed the hazard ratios (HRs) using the previously determined 47 μV TWA cutpoint. RESULTS During the 16 ± 7-month follow-up, 10 (4.4%) patients died suddenly. T-wave alternans (≥47 μV) predicted SCD (HR, 17.78 [95% confidence interval, 3.75-84.31]; P < .0001). Moreover, patients with 5 or more TWA episodes (≥47 μV) were at higher risk for SCD (HR, 20.75 [95% confidence interval, 5.77-74.57]; P < .0001). CONCLUSIONS T-wave alternans (≥47 μV) monitored at 1 to 15 days after AMI-predicted heightened risk of SCD. Prediction is improved when the frequency of TWA episodes (≥47 μV) is analyzed.
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Affiliation(s)
- Hou Yu
- Clinical Electrophysiology Laboratory and Arrhythmia Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Xicheng State, Beijing, China
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YAN GUOHUI, WANG MEI, YUE WENSHENG, YIU KAIHANG, ZHI GUANG, LAU CHUPAK, WL LEE STEPHEN, SIU CHUNGWAH, TSE HUNGFAT. Relationship between Ventricular Dyssynchrony and T-wave Alternans in Patients with Coronary Artery Disease. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2011; 34:1503-10. [DOI: 10.1111/j.1540-8159.2011.03183.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Secemsky EA, Verrier RL, Cooke G, Ghossein C, Subacius H, Manuchehry A, Herzog CA, Passman R. High prevalence of cardiac autonomic dysfunction and T-wave alternans in dialysis patients. Heart Rhythm 2011; 8:592-8. [DOI: 10.1016/j.hrthm.2010.11.041] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 11/24/2011] [Indexed: 11/28/2022]
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Chiu SN, Chiu HH, Wang JK, Lin MT, Chen CA, Wu ET, Lu CW, Wu MH. Increased microvolt T-wave alternans in patients with repaired tetralogy of Fallot. Int J Cardiol 2011; 159:220-4. [PMID: 21420183 DOI: 10.1016/j.ijcard.2011.02.063] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 01/19/2011] [Accepted: 02/25/2011] [Indexed: 11/16/2022]
Abstract
BACKGROUND Microvolt T wave alternans (MTWA) is an indicator of repolarization heterogeneity and a predictor of ventricular arrhythmia in adults with ischemic or dilated cardiomyopathy. Its implication in patients with repaired tetralogy of Fallot (TOF) is still unclear. This study sought to define the changes and the clinical implication of MTWA in these patients. METHODS Treadmill examination with modified moving average beat analysis (MMA) for MTWA was performed in 101 repaired TOF patients (60.4% male). Data from 103 age- and sex-matched subjects with normal hearts served as controls. RESULTS The age at latest follow-up was 20.0 ± 10.6 years. Total repair (60.4% received a transannular right ventricular outflow patch) was performed at a mean age of 4.8(± 5.8) years. After excluding 11 patients with indeterminate data, the MTWA data in 90 TOF patients revealed higher values than those in the control (25.1 ± 14.0 vs. 17.6 ± 9.2 μV, p<0.001). The values were best correlated to the presence of severe pulmonary regurgitation (p=0.006). Ten (9.9%) patients experienced late ventricular arrhythmic events. They tended to have higher MTWA values than those without (34.0 ± 16.5 vs. 24.2 ± 13.5 and p=0.053). Although the MTWA per se would not predict the late arrhythmia events better than QRS duration alone, the positive and negative predictive values increased slightly after adding the MTWA to QRS duration. CONCLUSIONS MTWA, as measured by MMA, increased in repaired TOF patients particularly in those with severe pulmonary regurgitation and late arrhythmia events. To predict late ventricular arrhythmia, MTWA however was not superior to QRS duration alone.
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Affiliation(s)
- Shuenn-Nan Chiu
- Department of Pediatrics, National Taiwan University Hospital and Medical College, National Taiwan University, Taipei, Taiwan
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Burattini L, Zareba W, Burattini R. Identification of gender-related normality regions for T-wave alternans. Ann Noninvasive Electrocardiol 2011; 15:328-36. [PMID: 20946555 DOI: 10.1111/j.1542-474x.2010.00388.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND T-wave alternans (TWA), a harbinger of sudden cardiac death, associates to a broad variety of pathologies. In a previous study, we observed the presence of unstable and low-amplitude TWA also in healthy subjects, and considered it as "physiological TWA." The possible existence of different TWA characteristics between males and female is investigated in the present work. METHODS Resting ECG recordings from 142 control healthy subjects, 77 males and 65 females, were submitted to our adaptive match filter (AMF) based method for TWA detection and characterization in terms of duration, amplitude, and their product. The 99.5th percentile of these parameters distributions over the entire control population and over the male and female subgroups, were used to define thresholds which delimit a gender-independent and male- and female-related TWA normality regions, respectively, out of which abnormal TWA cases (TWA+) are expected to fall. Clinical usefulness of these regions was tested using a population of 151 coronary artery disease (CAD) patients, divided into 128 males and 23 females. RESULTS In our control-female population, TWA duration was significantly longer than in control-male population (65 ± 13 beat vs 52 ± 14 beat; P < 10(-6) ). Our gender-related normality regions allowed identification of 36 (23.8%) TWA+ cases among the CAD patients, 17 more than those obtained from a gender-independent region. All these 17 patients were CAD males with over-threshold TWA duration. CONCLUSIONS TWA is a gender-related phenomenon. Definition of gender-related TWA normality regions improves identification of patients at increased TWA stability (i.e., prolonged TWA duration) and, thus, at increased risk of arrhythmic events.
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Affiliation(s)
- Laura Burattini
- Department of Biomedical, Electronics and Telecommunication Engineering, Polytechnic University of Marche, Ancona, Italy.
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Leino J, Verrier RL, Minkkinen M, Lehtimäki T, Viik J, Lehtinen R, Nikus K, Kööbi T, Turjanmaa V, Kähönen M, Nieminen T. Importance of regional specificity of T-wave alternans in assessing risk for cardiovascular mortality and sudden cardiac death during routine exercise testing. Heart Rhythm 2010; 8:385-90. [PMID: 21056698 DOI: 10.1016/j.hrthm.2010.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 11/01/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND T-wave alternans (TWA) indicates increased risk for life-threatening arrhythmias. However, the regional distribution and predictivity of TWA among precordial leads remain unknown. OBJECTIVE We analyzed the magnitude and prognostic power of TWA in precordial leads separately and in combination during routine exercise stress testing in the largest TWA study conducted to date. METHODS The Finnish Cardiovascular Study (FINCAVAS) enrolled consecutive patients (n = 3,598, 56 ± 13 [mean ± standard deviation] years old, 2,164 men, 1,434 women) with a clinically indicated exercise test with bicycle ergometer. TWA was analyzed with the time-domain modified moving average method. RESULTS During a follow-up of 55 months (interquartile range of 35-78 months), 231 patients died; 97 deaths were cardiovascular, and 46 were classified as sudden cardiac deaths (SCDs). In Cox analysis after adjustment for common coronary risk factors, each 20-μV increase in TWA in leads V1-V6 multiplied the hazard ratio for cardiovascular mortality by 1.486-fold (95% confidence interval [CI] 1.127-1.952; P = .005). Each 20-μV increase in TWA in lead V5 amplified the hazard ratio for cardiovascular mortality by 1.545 (95% CI 1.150-2.108; P = .004) and for SCD by 1.576 (95% CI 1.041-2.412; P = .033). CONCLUSIONS Maximum TWA monitored from anterolateral precordial lead V5 is the strongest predictor of cardiovascular mortality and SCD during routine exercise testing in our analysis. Higher TWA values indicate greater cardiovascular mortality and SCD risk, supporting the concept that quantification of TWA should receive more attention.
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Nieminen T, Verrier RL. Usefulness of T-wave alternans in sudden death risk stratification and guiding medical therapy. Ann Noninvasive Electrocardiol 2010; 15:276-88. [PMID: 20645971 PMCID: PMC6932425 DOI: 10.1111/j.1542-474x.2010.00376.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Visible T-wave alternans (TWA), a beat-to-beat alternation in the morphology and amplitude of the ST segment or T wave, has been observed for over a century to occur in association with life-threatening arrhythmias in patients with acute coronary syndrome, heart failure, and cardiac channelopathies. This compelling linkage prompted development of quantitative techniques leading to FDA-cleared commercial methodologies for measuring nonvisible levels of TWA in the frequency and time domains. The first aim of this review is to summarize evidence from more than a hundred studies enrolling a total of >12,000 patients that support the predictivity of TWA for cardiovascular mortality and sudden cardiac death. The second focus is on the usefulness of TWA in guiding therapy. Until recently, TWA has been used primarily in decision making for cardioverter-defibrillator implantation. Its potential utility in guiding pharmacologic therapy has been underappreciated. We review clinical literature supporting the usefulness of TWA as an index of antiarrhythmic effects and proarrhythmia for different drug classes. Beta-adrenergic and sodium channel-blocking agents are the most widely studied drugs in clinical TWA investigations, with both reducing TWA magnitude; the exception is patients in whom sodium channel blockade discloses the Brugada syndrome and provokes macroscopic TWA. An intriguing possibility is that TWA may help to detect beneficial effects of nonantiarrhythmic agents such as the angiotensin II receptor blocker valsartan, which indirectly protects from arrhythmia through improving myocardial remodeling. We conclude that quantitative analysis of TWA has considerable potential to guide pharmacologic intervention and thereby serve as a therapeutic target.
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Affiliation(s)
- Tuomo Nieminen
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
- Department of Pharmacological Sciences, Medical School, University of Tampere, Finland, and Department of Internal Medicine, Päijät‐Häme Central Hospital, Lahti, Finland
| | - Richard L. Verrier
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
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A multilead scheme based on periodic component analysis for T-wave alternans analysis in the ECG. Ann Biomed Eng 2010; 38:2532-41. [PMID: 20387121 DOI: 10.1007/s10439-010-0029-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 03/27/2010] [Indexed: 10/19/2022]
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 (piCA), 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 piCA-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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Stein PK, Sanghavi D, Sotoodehnia N, Siscovick DS, Gottdiener J. Association of Holter-based measures including T-wave alternans with risk of sudden cardiac death in the community-dwelling elderly: the Cardiovascular Health Study. J Electrocardiol 2010; 43:251-9. [PMID: 20096853 DOI: 10.1016/j.jelectrocard.2009.12.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Indexed: 11/29/2022]
Abstract
BACKGROUND Sudden cardiac death (SCD) can be the first manifestation of cardiovascular disease. Development of screening methods for higher/lower risk is critical. METHODS The Cardiovascular Health Study is a population-based study of risk factors for coronary heart disease and stroke those 65 years or older. Forty-nine (of 1649) with usable Holters and in normal sinus rhythm had SCD during follow-up and were matched with 2 controls, alive at the time of death of the case and not experiencing SCD on follow-up. Univariate and multivariate conditional logistic regression determined the association of Holter-based information and SCD. RESULTS In univariate models, the upper half of ventricular premature contraction (VPC) counts, abnormal heart rate turbulence, decreased normalized low-frequency power, increased T-wave alternans (TWA), and decreased the short-term fractal scaling exponent (DFA(1)) were associated with SCD, but time domain heart rate variability was not. In multivariate models, the upper half of VPC counts (odds ratio [OR], 6.6) and having TWA of 37 muV or greater on channel 2 (OR, 4.8) were independently associated with SCD. Also, the upper half of VPC counts (OR, 6.9) and having a DFA(1) of less than 1.05 (OR, 5.0) were independently associated with SCD. When additive effects were explored, having both higher VPCs and higher TWA was associated with an OR of 8.2 for SCD compared with 2.6 for having either. Also, having both higher VPCs and lower DFA(1) was associated with an OR of 9.6 for SCD compared with 3.1 for having either. CONCLUSIONS Results support a potential role for 24-hour Holter recordings to identify older adults at increased or lower risk of SCD.
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Affiliation(s)
- Phyllis K Stein
- Washington University School of Medicine, 4625 Lindell Blvd., St. Louis, MO 63108, USA.
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Combined assessment of heart rate recovery and T-wave alternans during routine exercise testing improves prediction of total and cardiovascular mortality: The Finnish Cardiovascular Study. Heart Rhythm 2009; 6:1765-71. [DOI: 10.1016/j.hrthm.2009.08.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Accepted: 08/12/2009] [Indexed: 11/21/2022]
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Abstract
Heart rate is a precisely regulated variable, which plays a critical role in health and disease. Numerous epidemiologic studies and large post-myocardial infarction trials have provided evidence that elevated resting heart rate is an independent risk factor for cardiac mortality. This body of knowledge has prompted the development and evaluation of negative chronotropic agents, prototypically the I(f) inhibitor Ivabradine. The present review addresses several fundamental questions: (1) How is heart rate regulated at the integrative, cellular, and molecular levels? (2) How are autonomic tone and reflexes measured clinically, and what is the prognostic utility of these parameters? (3) What mechanisms are responsible for the cardiovascular pathology associated with elevated heart rates? (4) Does reducing heart rate independent of effects on other factors protect against cardiovascular events?
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Chicos AB, Kannankeril PJ, Kadish AH, Goldberger JJ. Parasympathetic effects on cardiac electrophysiology during exercise and recovery in patients with left ventricular dysfunction. Am J Physiol Heart Circ Physiol 2009; 297:H743-9. [PMID: 19525382 DOI: 10.1152/ajpheart.00193.2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Depressed parasympathetic activity has been proposed to be associated with an increased risk of sudden death. Parasympathetic effects (PE) on cardiac electrophysiology during exercise and recovery have not been studied in patients with left ventricular dysfunction. We performed noninvasive electrophysiological studies (NI-EPS) and characterized the electrophysiological properties of the sinus node, atrioventricular (AV) node, and ventricle in subjects with depressed left ventricular ejection fraction and dual-chamber defibrillators. NI-EPS were performed during rest, exercise, and recovery at baseline and after parasympathetic blockade with atropine to assess PE (the difference between parameter values in the 2 conditions). Ten subjects (9 men: age, 60 +/- 9 yr; and left ventricular ejection fraction, 29 +/- 8%) completed the study. All NI-EPS parameters decreased during exercise and trended toward rest values during recovery. PE at rest, during exercise, and during recovery, respectively, were on sinus cycle length, 320 +/- 71 (P = 0.0001), 105 +/- 60 (P = 0.0003), and 155 +/- 82 ms (P = 0.0002); on AV block cycle length, 137 +/- 136 (P = 0.09), 37 +/- 19 (P = 0.002), and 61 +/- 39 ms (P = 0.006); on AV interval, 58 +/- 32 (P = 0.035), 22 +/- 13 (P = 0.002), and 36 +/- 20 ms (P = 0.001); on ventricular effective refractory period, 15.8 +/- 11.3 (P = 0.02), 4.7 +/- 15.2 (P = 0.38), and 6.8 +/- 15.5 ms (P = 0.20); and on QT interval, 13 +/- 12 (P = 0.13), 3 +/- 17 (P = 0.6), and 20 +/- 23 (P = 0.04). In conclusion, we describe for the first time the changes in cardiac electrophysiology and PE during rest, exercise, and recovery in subjects with left ventricular dysfunction. PEs are preserved in these patients. Thus the role of autonomic changes in the pathophysiology of sudden death requires further exploration.
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Affiliation(s)
- Alexandru B Chicos
- Division of Cardiology, Bluhm Cardiovascular Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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To the Editor:. J Cardiovasc Electrophysiol 2009. [DOI: 10.1111/j.1540-8167.2009.01491.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: 11/27/2022]
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To the Editor:. J Cardiovasc Electrophysiol 2009; 20:E65; author reply E64. [DOI: 10.1111/j.1540-8167.2009.01492.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]
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Verrier RL, Kumar K, Nearing BD. Basis for sudden cardiac death prediction by T-wave alternans from an integrative physiology perspective. Heart Rhythm 2009; 6:416-22. [PMID: 19251221 PMCID: PMC2672309 DOI: 10.1016/j.hrthm.2008.11.019] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
Abstract
Detection of microvolt levels of T-wave alternans (TWA) has been shown to be useful in identifying individuals at heightened risk for sudden cardiac death. The mechanistic bases for TWA are complex, at the cellular level involving multiple mechanisms, particularly instabilities in membrane voltage (i.e., steep action potential duration restitution slope) and disruptions in intracellular calcium cycling dynamics. The integrative factors influencing TWA at the systemic level are also multifold. We focus on three main variables: heart rate, autonomic nervous system activity, and myocardial ischemia. Clinically, there is growing interest in extending TWA testing to include ambulatory ECG monitoring as well as exercise. The former modality permits assessment of the influence of diverse provocative stimuli of daily life, including physical activity, circadian factors, mental stress, and sleep-state related disturbances in respiratory and cardiovascular function. Two major emerging concepts in clinical TWA testing are discussed: quantitative analysis of TWA level to complement the current binary classification scheme, and risk stratification of patients with preserved left ventricular function, the population with the largest absolute number of sudden cardiac deaths.
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Affiliation(s)
- Richard L Verrier
- Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Cardiovascular Institute, Boston, Massachusetts 02115, USA.
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Abstract
Microvolt-level T-wave alternans (TWA) is a new arrhythmia risk marker to assess subtle changes in repolarization that has been introduced for arrhythmia risk stratification. Recent experimental studies have demonstrated that it reflects a heartrate dependent increased spatial dispersion of repolarization associated with unidirectional conduction block, and reentry that may result in the occurrence of ventricular fibrillation. Clinical studies have convincingly demonstrated that TWA is closely related to arrhythmia induction in the electrophysiology (EP) laboratory as well as to the occurrence of spontaneous ventricular tachyarrhythmias in patients undergoing EP study. Subsequent studies showed that TWA-assessed noninvasively-is predictive of future arrhythmic events in patients with implanted ICDs as well as for ventricular tachyarrhythmias in patients with congestive heart failure without a prior history of arrhythmias. There is still controversy, however, about the predictive value of TWA in patients following acute myocardial infarction (MI). Several studies which differ in patient selection, pharmacologic treatment of the patients, and endpoint definitions, have reported conflicting results. Therefore, studies with a large number of unselected patients after acute MI on optimal treatment according to contemporary therapeutic guidelines as well as of patients with reduced left ventricular ejection fraction following MI are needed to define its role with regard to identifying patients who may benefit from primary preventive ICD therapy. Future research should also focus on evaluation of alternative methods to increase heart rate (i.e., pharmacological stimulation) in an attempt to reduce the proportion of incomplete tests in patients with insufficient increase in heart rate during exercise testing.
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