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Nearing BD, Verrier RL. Novel application of convolutional neural networks for artificial intelligence-enabled modified moving average analysis of P-, R-, and T-wave alternans for detection of risk for atrial and ventricular arrhythmias. J Electrocardiol 2024; 83:12-20. [PMID: 38185007 DOI: 10.1016/j.jelectrocard.2023.12.012] [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: 10/24/2023] [Revised: 12/22/2023] [Accepted: 12/22/2023] [Indexed: 01/09/2024]
Abstract
BACKGROUND T-wave alternans (TWA) analysis was shown in >14,000 individuals studied worldwide over the past two decades to be a useful tool to assess risk for cardiovascular mortality and sudden arrhythmic death. TWA analysis by the modified moving average (MMA) method is FDA-cleared and CMS-reimbursed (CAG-00293R2). OBJECTIVE Because the MMA technique is inherently suitable for dynamic tracking of alternans levels, it was selected for development of artificial intelligence (AI)-enabled algorithms using convolutional neural networks (CNN) to achieve rapid, efficient, and accurate assessment of P-wave alternans (PWA), R-wave alternans (RWA), and TWA. METHODS The novel application of CNN algorithms to enhance MMA analysis generated efficient and powerful pattern-recognition algorithms for highly accurate alternans quantification. Algorithm reliability and accuracy were verified using simulated ECGs achieving R2 ≥ 0.99 (p < 0.01) in response to noise inputs and artifacts that emulate real-life conditions. RESULTS Accuracy of the new AI-MMA algorithms in TWA analysis (n = 5) was significantly improved over unsupervised, automated MMA output (p = 0.036) and did not differ from conventional MMA analysis with expert overreading (p = 0.21). Accuracy of AI-MMA in PWA analysis (n = 45) was significantly improved over unsupervised, automated MMA output (p < 0.005) and did not differ from conventional MMA analysis with expert overreading (p = 0.89). TWA and PWA by AI-MMA were correlated with conventional MMA output over-read by an expert reader (R2 = 0.7765, R2 = 0.9504, respectively). CONCLUSION This novel technique for AI-MMA analysis could be suitable for use in diverse in-hospital and out-of-hospital monitoring systems, including cardiac implantable electronic devices and smartwatches, for tracking atrial and ventricular arrhythmia risk.
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Affiliation(s)
- Bruce D Nearing
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Richard L Verrier
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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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] [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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Verrier RL, Nearing BD, D'Avila A. Spectrum of clinical applications of interlead ECG heterogeneity assessment: From myocardial ischemia detection to sudden cardiac death risk stratification. Ann Noninvasive Electrocardiol 2021; 26:e12894. [PMID: 34592018 PMCID: PMC8588374 DOI: 10.1111/anec.12894] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/23/2021] [Accepted: 09/03/2021] [Indexed: 12/11/2022] Open
Abstract
Heterogeneity in depolarization and repolarization among regions of cardiac cells has long been recognized as a major factor in cardiac arrhythmogenesis. This fundamental principle has motivated development of noninvasive techniques for quantification of heterogeneity using the surface electrocardiogram (ECG). The initial approaches focused on interval analysis such as interlead QT dispersion and Tpeak -Tend difference. However, because of inherent difficulties in measuring the termination point of the T wave and commonly encountered irregularities in the apex of the T wave, additional techniques have been pursued. The newer methods incorporate assessment of the entire morphology of the T wave and in some cases of the R wave as well. This goal has been accomplished using a number of promising vectorial approaches with the resting 12-lead ECG. An important limitation of vectorcardiographic analyses is that they require exquisite stability of the recordings and are not inherently suitable for use in exercise tolerance testing (ETT) and/or ambulatory ECG monitoring for provocative stress testing or evaluation of the influence of daily activities on cardiac electrical instability. The objectives of the present review are to describe a technique that has been under clinical evaluation for nearly a decade, termed "interlead ECG heterogeneity." Preclinical testing data will be briefly reviewed. We will discuss the main clinical findings with regard to sudden cardiac death risk stratification, heart failure evaluation, and myocardial ischemia detection using standard recording platforms including resting 12-lead ECG, ambulatory ECG monitoring, ETT, and pharmacologic stress testing in conjunction with single-photon emission computed tomography myocardial perfusion imaging.
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Affiliation(s)
- Richard L Verrier
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Bruce D Nearing
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Andre D'Avila
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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Kulkarni K, Stavrakis S, Elkholey K, Singh JP, Parks KA, Armoundas AA. Microvolt T-Wave Alternans Is Modulated by Acute Low-Level Tragus Stimulation in Patients With Ischemic Cardiomyopathy and Heart Failure. Front Physiol 2021; 12:707724. [PMID: 34366894 PMCID: PMC8343129 DOI: 10.3389/fphys.2021.707724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/30/2021] [Indexed: 12/15/2022] Open
Abstract
Aims: Microvolt T-wave alternans (TWA), an oscillation in T-wave morphology of the electrocardiogram (ECG), has been associated with increased susceptibility to ventricular tachy-arrhythmias, while vagus nerve stimulation has shown promising anti-arrhythmic effects in in vivo and ex vivo animal studies. We aimed to examine the effect of non-invasive, acute low-level tragus stimulation (LLTS) on TWA in patients with ischemic cardiomyopathy and heart failure. Methods: 26 patients with ischemic cardiomyopathy (left ventricular ejection fraction <35%) and chronic stable heart failure, previously implanted with an automatic implantable cardioverter defibrillator (ICD) device with an atrial lead (dual chamber ICD or cardiac resynchronization therapy defibrillator), were enrolled in the study. Each patient sequentially received, (1) Sham LLTS (electrode on tragus, but no stimulation delivered) for 5 min; (2) Active LLTS at two different frequencies (5 and 20 Hz, 15 min each); and (3) Active LLTS, during concomitant atrial pacing at 100 bpm at two different frequencies (5 and 20 Hz, 15 min each). LLTS was delivered through a transcutaneous electrical nerve stimulation device (pulse width 200 μs, frequency 5/20 Hz, amplitude 1 mA lower than the discomfort threshold). TWA burden was assessed using continuous ECG monitoring during sham and active LLTS in sinus rhythm, as well as during atrial pacing. Results: Right atrial pacing at 100 bpm led to significantly heightened TWA burden compared to sinus rhythm, with or without LLTS. Acute LLTS at both 5 and 20 Hz, during sinus rhythm led to a significant rise in TWA burden in the precordial leads (p < 0.05). Conclusion: Acute LLTS results in a heart-rate dependent increase in TWA burden.
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Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States
| | - Stavros Stavrakis
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Khaled Elkholey
- Heart Rhythm Institute, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, United States
| | - Kimberly A Parks
- Cardiology Division, Brigham and Women's Hospital, Boston, MA, United States
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
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Spatial variance in the 12-lead ECG and mechanical dyssynchrony. J Interv Card Electrophysiol 2021; 62:479-485. [PMID: 34014454 DOI: 10.1007/s10840-021-00999-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/15/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Electrical transmission disorders have a deleterious effect on cardiac depolarization, resulting in a disorganized ventricular contraction that reduces global mechanical efficiency; this mechanical dyssynchrony can be corrected by cardiac resynchronization therapy. However, despite adjustments in the electrical criteria selection of QRS for the recognition of mechanical dyssynchrony, a significant proportion of patients do not currently respond to this therapy. PURPOSE To find if a new predictor of dyssynchrony, the electrocardiogram spatial variance, is a better marker of mechanical dyssynchrony than QRS duration. METHODS Forty-seven electrocardiograms and 47 strain (2D speckle tracking) echocardiograms were prospectively collected simultaneously in consecutive, non-selected patients; the left ventricular mechanical dispersion was measured in all the cases. The electrocardiographic analysis of variance was made with a digital superposition of the electrocardiographic leads and generates different indexes of variance of both QRS complex and repolarization phase. RESULTS ROC analysis probed that the best area under the curve (AUC) value correlated with left ventricular mechanical dispersion and was obtained combining several spatial variance markers (considering depolarization and repolarization spatial variance together; AUC = 0.97); the same analysis using the QRS duration versus mechanical dispersion showed a significantly lower AUC value (AUC = 0.64). CONCLUSION Spatial variance combining depolarization and repolarization markers is a superior predictor of left ventricular mechanical dispersion than QRS duration.
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Martins C, Machado da Silva J, Guimarães D, Martins L, Vaz da Silva M. MONITORIA: The start of a new era of ambulatory heart failure monitoring? Part I - Theoretical Rationale. Rev Port Cardiol 2021; 40:329-337. [PMID: 34187634 DOI: 10.1016/j.repce.2020.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 07/28/2020] [Indexed: 10/21/2022] Open
Abstract
Heart failure (HF) is a multifactorial chronic syndrome with progressive increasing incidence causing a huge financial burden worldwide. Remote monitoring should, in theory, improve HF management, but given increasing morbidity and mortality, a question remains: are we monitoring it properly? Device-based home monitoring enables objective and continuous measurement of vital variables and non-invasive devices should be first choice for elderly patients. There is no shortage of literature on the subject, however, most studies were designed to monitor a single variable or class of variables that were not properly assembled and, to the best of our knowledge, there are no large randomized studies about their impact on HF patient management. To overcome this problem, we carefully selected the most critical possible HF decompensating factors to design MONITORIA, a non-invasive device for comprehensive HF home monitoring. MONITORIA stands for MOnitoring Non-Invasively To Overcome mortality Rates of heart Insufficiency on Ambulatory, and in this paper, which is part I of a series of three articles, we discuss the theoretical basis for its design. MONITORIA and its inherent follow-up strategy will optimize HF patient care as it is a promising device, which will essentially adapt innovation not to the disease but rather to the patients.
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Affiliation(s)
- Carla Martins
- Internal Medicine, Centro Hospitalar de Entre Douro e Vouga, Santa Maria da Feira, Portugal.
| | | | - Diana Guimarães
- Faculty of Engineering of the University of Porto, Porto, Portugal
| | - Luís Martins
- Cardiology, Centro Hospitalar de Entre Douro e Vouga, Santa Maria da Feira, Portugal
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7
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MONITORIA: The start of a new era of ambulatory heart failure monitoring? Part I - Theoretical Rationale. Rev Port Cardiol 2021; 40:329-337. [PMID: 33483175 DOI: 10.1016/j.repc.2020.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 05/22/2020] [Accepted: 07/28/2020] [Indexed: 11/23/2022] Open
Abstract
Heart failure (HF) is a multifactorial chronic syndrome with progressive increasing incidence causing a huge financial burden worldwide. Remote monitoring should, in theory, improve HF management, but given increasing morbidity and mortality, a question remains: are we monitoring it properly? Device-based home monitoring enables objective and continuous measurement of vital variables and non-invasive devices should be first choice for elderly patients. There is no shortage of literature on the subject, however, most studies were designed to monitor a single variable or class of variables that were not properly assembled and, to the best of our knowledge, there are no large randomized studies about their impact on HF patient management. To overcome this problem, we carefully selected the most critical possible HF decompensating factors to design MONITORIA, a non-invasive device for comprehensive HF home monitoring. MONITORIA stands for MOnitoring Non-Invasively To Overcome mortality Rates of heart Insufficiency on Ambulatory, and in this paper, which is part I of a series of three articles, we discuss the theoretical basis for its design. MONITORIA and its inherent follow-up strategy will optimize HF patient care as it is a promising device, which will essentially adapt innovation not to the disease but rather to the patients.
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Merchant FM, Sayadi O, Sohn K, Weiss EH, Puppala D, Doddamani R, Singh JP, Heist EK, Owen C, Kulkarni K, Armoundas AA. Real-Time Closed-Loop Suppression of Repolarization Alternans Reduces Arrhythmia Susceptibility In Vivo. Circ Arrhythm Electrophysiol 2020; 13:e008186. [PMID: 32434448 DOI: 10.1161/circep.119.008186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. METHODS We have developed a real-time, closed-loop system to record and analyze RA from multiple intracardiac leads, and deliver dynamically R-wave triggered pacing stimuli during the absolute refractory period. We have evaluated the ability of this system to control RA and reduce arrhythmia susceptibility, in vivo. RESULTS R-wave triggered pacing can induce RA, the magnitude of which can be modulated by varying the amplitude, pulse width, and size of the pacing vector. Using a swine model (n=9), we demonstrate that to induce a 1 µV change in the alternans voltage on the body surface, coronary sinus and left ventricle leads, requires a delivered charge of 0.04±0.02, 0.05±0.025, and 0.06±0.033 µC, respectively, while to induce a one unit change of the Kscore, requires a delivered charge of 0.93±0.73, 0.32±0.29, and 0.33±0.37 µC, respectively. For all body surface and intracardiac leads, both Δ(alternans voltage) and ΔKscore between baseline and R-wave triggered paced beats increases consistently with an increase in the pacing pulse amplitude, pulse width, and vector spacing. Additionally, we show that the proposed method can be used to suppress spontaneously occurring alternans (n=7), in the presence of myocardial ischemia. Suppression of RA by pacing during the absolute refractory period results in a significant reduction in arrhythmia susceptibility, evidenced by a lower Srank score during programmed ventricular stimulation compared with baseline before ischemia. CONCLUSIONS We have developed and evaluated a novel closed-loop method to dynamically modulate RA in a swine model. Our data suggest that suppression of RA directly reduces arrhythmia susceptibility and reinforces the concept that RA plays a critical role in the pathophysiology of arrhythmogenesis.
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Affiliation(s)
- Faisal M Merchant
- Cardiology Division, Emory University School of Medicine, Atlanta, GA (F.M.M.).,Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Omid Sayadi
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Kwanghyun Sohn
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Eric H Weiss
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge (E.H.W., A.A.A.)
| | - Dheeraj Puppala
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Rajiv Doddamani
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service (J.P.S., E.K.H.), Massachusetts General Hospital, Boston
| | - E Kevin Heist
- Cardiology Division, Cardiac Arrhythmia Service (J.P.S., E.K.H.), Massachusetts General Hospital, Boston
| | - Chris Owen
- Neurosurgery Division (C.O.), Massachusetts General Hospital, Boston
| | - Kanchan Kulkarni
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston
| | - Antonis A Armoundas
- Cardiovascular Research Center (F.M.M., O.S., K.S., E.H.W., D.P., R.D., K.K., A.A.A.), Massachusetts General Hospital, Boston.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge (E.H.W., A.A.A.)
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9
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Silva AC, de Antonio VZ, Sroubek J, Gervino E, Ho K, Medeiros SA, Silva FT, Pedreira GC, Stocco FG, Nearing BD, Verrier RL. Exercise and pharmacologic stress-induced interlead T-wave heterogeneity analysis to detect clinically significant coronary artery stenosis. Int J Cardiol 2020; 298:32-38. [PMID: 31412992 DOI: 10.1016/j.ijcard.2019.07.066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/08/2019] [Accepted: 07/22/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND Despite widespread use of ETT and vasodilator-stress with myocardial perfusion imaging (MPI) for noninvasive detection of flow-limiting coronary artery disease, there is continued need to improve diagnostic accuracy. We examined whether measurement of interlead T-wave heterogeneity (TWH) during exercise tolerance testing (ETT) or pharmacologic stress testing improves detection of stenoses in large epicardial coronary arteries. METHODS All 137 patients at our institution who underwent diagnostic coronary angiography within 0 to 5 days after ETT (N = 81) or dipyridamole IV infusion (N = 58) in 2016 were studied, including 2 patients with both tests. Cases (N = 93) had angiographically significant stenosis (≥50% of left main or ≥ 70% of an epicardial coronary artery ≥2 mm in diameter); controls (N = 44) did not. TWH, i.e., interlead splay of T waves, was determined by second central moment analysis from precordial leads by an investigator blinded to angiographic results. RESULTS At rest, TWH levels were similar for cases and controls. ETT and dipyridamole stress testing increased TWH by 69% (p < 0.0001) and 27% (p < 0.0001), respectively, in cases. In controls, TWH did not change. Areas under the ROC curves for TWH increase for any flow-limiting coronary artery stenosis were 0.737 (p < 0.0001) for ETT and 0.818 (p < 0.0001) for dipyridamole stress testing. By contrast, neither ST-segment changes during ETT (p = 0.12) nor MPI during dipyridamole stress testing (p = 0.60) discriminated cases from controls. CONCLUSIONS TWH measurement is a novel method that improves detection of angiographically confirmed flow-limiting stenoses in large epicardial coronary arteries during both ETT and MPI during pharmacologic stress testing with dipyridamole.
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Affiliation(s)
- Anderson C Silva
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Victor Z de Antonio
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Jakub Sroubek
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Ernest Gervino
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Kalon Ho
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Sofia A Medeiros
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Fernanda Tessarolo Silva
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Giovanna C Pedreira
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Fernando G Stocco
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Bruce D Nearing
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America
| | - Richard L Verrier
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Cardiovascular Medicine, Boston, MA, United States of America; Harvard School of Public Health, Department of Environmental Sciences, Boston, MA, United States of America; Harvard Medical School, Department of Medicine, Boston, MA, United States of America.
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10
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Kulkarni K, Merchant FM, Kassab MB, Sana F, Moazzami K, Sayadi O, Singh JP, Heist EK, Armoundas AA. Cardiac Alternans: Mechanisms and Clinical Utility in Arrhythmia Prevention. J Am Heart Assoc 2019; 8:e013750. [PMID: 31617437 PMCID: PMC6898836 DOI: 10.1161/jaha.119.013750] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | | | - Mohamad B. Kassab
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Furrukh Sana
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Kasra Moazzami
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Omid Sayadi
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Jagmeet P. Singh
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - E. Kevin Heist
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - Antonis A. Armoundas
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
- Institute for Medical Engineering and ScienceMassachusetts Institute of TechnologyCambridgeMA
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11
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Sohn K, Dalvin SP, Merchant FM, Kulkarni K, Sana F, Abohashem S, Singh JP, Heist EK, Owen C, Isselbacher EM, Armoundas AA. Utility of a Smartphone Based System (cvrPhone) to Predict Short-term Arrhythmia Susceptibility. Sci Rep 2019; 9:14497. [PMID: 31601824 PMCID: PMC6787075 DOI: 10.1038/s41598-019-50487-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 09/10/2019] [Indexed: 01/27/2023] Open
Abstract
Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. We developed a 12-lead, blue-tooth/Smart-Phone (Android) based electrocardiogram (ECG) acquisition and monitoring system (cvrPhone), and an application to estimate RA, in real-time. In in-vivo swine studies (N = 17), 12-lead ECG signals were recorded at baseline and following coronary artery occlusion. RA was estimated using the Fast Fourier Transform (FFT) method using a custom developed algorithm in JAVA. Underlying ischemia was detected using a custom developed ischemic index. RA from each lead showed a significant (p < 0.05) increase within 1 min of occlusion compared to baseline (n = 29). Following myocardial infarction, spontaneous ventricular tachycardia episodes (n = 4) were preceded by significant (p < 0.05) increase of RA prior to the onset of the tachy-arrhythmias. Similarly, the ischemic index exhibited a significant increase following myocardial infarction (p < 0.05) and preceding a tachy-arrhythmic event. In conclusion, RA can be effectively estimated using surface lead electrocardiograms by analyzing beat-to-beat variability in ECG morphology using a smartphone based platform. cvrPhone can be used to detect myocardial ischemia and arrhythmia susceptibility using a user-friendly, clinically acceptable, mobile platform.
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Affiliation(s)
- Kwanghyun Sohn
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Steven P Dalvin
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Faisal M Merchant
- Cardiology Division, Emory, University School of Medicine, Atlanta, GA, USA
| | - Kanchan Kulkarni
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Furrukh Sana
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Shady Abohashem
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Jagmeet P Singh
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, USA
| | - E Kevin Heist
- Cardiology Division, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA, USA
| | - Chris Owen
- Neurosurgery Division, Massachusetts General Hospital, Boston, MA, USA
| | - Eric M Isselbacher
- Healthcare Transformation Lab, Massachusetts General Hospital, Boston, MA, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA. .,Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge, MA, USA.
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12
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Bonomini MP, Ortega DF, Barja LD, Mangani N, Arini PD. Depolarization spatial variance as a cardiac dyssynchrony descriptor. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2018.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Stocco FG, Evaristo E, Shah NR, Cheezum MK, Hainer J, Foster C, Nearing BD, Gervino E, Verrier RL. Marked exercise-induced T-wave heterogeneity in symptomatic diabetic patients with nonflow-limiting coronary artery stenosis. Ann Noninvasive Electrocardiol 2018; 23:e12503. [PMID: 28949056 PMCID: PMC6495190 DOI: 10.1111/anec.12503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/26/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND T-wave heterogeneity (TWH) independently predicted cardiovascular mortality in Health Survey 2000 based on 12-lead ECGs recorded at rest. We investigated whether TWH is elevated during exercise tolerance testing (ETT) in symptomatic diabetic patients with nonflow-limiting coronary artery stenosis compared to control subjects without diabetes. METHODS Cases were all patients (n = 20) with analyzable ECG recordings during both rest and ETT who were enrolled in the Effects of Ranolazine on Coronary Flow Reserve (CFR) in Symptomatic Patients with Diabetes and Suspected or Known Coronary Artery Disease (RAND-CFR) study (NCT01754259); median CFR was 1.44; 80% of cases had CFR <2. Control subjects (n = 9) were nondiabetic patients who had functional flow reserve (FFR) >0.8, a range not associated with inducible ischemia. TWH was analyzed from precordial leads V4 , V5 , and V6 by second central moment analysis, which assesses the interlead splay of T-waves about a mean waveform. RESULTS During exercise to similar rate-pressure products (p = .31), RAND-CFR patients exhibited a 49% increase in TWH during exercise (rest: 49 ± 5 μV; exercise: 73 ± 8 μV, p = .003). By comparison, in control subjects, TWH was not significantly altered (rest: 52 ± 11 μV; ETT: 38 ± 5 μV, p = .19). ETT-induced ST-segment depression >1 mm (p = .11) and Tpeak -Tend (p = .18) and QTc intervals (p = .80) failed to differentiate cases from controls. CONCLUSIONS TWH is capable of detecting latent repolarization abnormalities, which are present during ETT in diabetic patients with nonflow-limiting stenosis but not in control subjects. The technique developed in this study permits TWH analysis from archived ECGs and thereby enables mining of extensive databases for retrospective studies and hypothesis testing.
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Affiliation(s)
- Fernando G. Stocco
- University of Sao Paulo School of MedicineSao PauloBrazil
- Beth Israel Deaconess Medical CenterBostonMAUSA
| | - Ederson Evaristo
- University of Sao Paulo School of MedicineSao PauloBrazil
- Beth Israel Deaconess Medical CenterBostonMAUSA
| | - Nishant R. Shah
- Brigham & Women's HospitalBostonMAUSA
- Harvard Medical SchoolBostonMAUSA
- Brown University Warren Alpert Medical SchoolProvidenceRIUSA
| | | | | | | | - Bruce D. Nearing
- Beth Israel Deaconess Medical CenterBostonMAUSA
- Harvard Medical SchoolBostonMAUSA
| | - Ernest Gervino
- Beth Israel Deaconess Medical CenterBostonMAUSA
- Harvard Medical SchoolBostonMAUSA
| | - Richard L. Verrier
- Beth Israel Deaconess Medical CenterBostonMAUSA
- Harvard Medical SchoolBostonMAUSA
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14
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Bui AH, Waks JW. Risk Stratification of Sudden Cardiac Death After Acute Myocardial Infarction. J Innov Card Rhythm Manag 2018; 9:3035-3049. [PMID: 32477797 PMCID: PMC7252689 DOI: 10.19102/icrm.2018.090201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/02/2017] [Indexed: 01/20/2023] Open
Abstract
Despite advances in the diagnosis and treatment of acute coronary syndromes and an overall improvement in outcomes, mortality after myocardial infarction (MI) remains high. Sudden death, which is most frequently due to ventricular tachycardia or ventricular fibrillation, is the cause of death in 25% to 50% of patients with prior MI, and therefore represents an important public health problem. Use of the implantable cardioverter-defibrillator (ICD), which is the primary method of reducing the chance of arrhythmic sudden death after MI, is costly to the medical system and is associated with procedural and long-term risks. Additionally, assessment of left ventricular ejection fraction (LVEF), which is the primary method of assessing a patient's post-MI sudden death risk and appropriateness for ICD implantation, lacks both sensitivity and specificity for sudden death, and may not be the optimal way to select the subgroup of post-MI patients who are most likely to benefit from ICD implantation. To optimally utilize ICDs, it is therefore critical to develop and prospectively validate sudden death risk stratification methods beyond measuring LVEF. A variety of tests that assess left ventricular systolic function/morphology, potential triggers for ventricular arrhythmias, ventricular conduction/repolarization, and autonomic tone have been proposed as sudden death risk stratification tools. Multivariable models have also been developed to assess the competing risks of arrhythmic and non-arrhythmic death so that ICDs can be utilized more effectively. This manuscript will review the epidemiology of sudden death after MI, and will discuss the current state of sudden death risk stratification in this population.
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Affiliation(s)
- An H. Bui
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jonathan W. Waks
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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15
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Kenttä TV, Sinner MF, Nearing BD, Freudling R, Porthan K, Tikkanen JT, Müller-Nurasyid M, Schramm K, Viitasalo M, Jula A, Nieminen MS, Peters A, Salomaa V, Oikarinen L, Verrier RL, Kääb S, Junttila MJ, Huikuri HV. Repolarization Heterogeneity Measured With T-Wave Area Dispersion in Standard 12-Lead ECG Predicts Sudden Cardiac Death in General Population. Circ Arrhythm Electrophysiol 2018; 11:e005762. [DOI: 10.1161/circep.117.005762] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 12/18/2017] [Indexed: 11/16/2022]
Affiliation(s)
- Tuomas V. Kenttä
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Moritz F. Sinner
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Bruce D. Nearing
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Rebecca Freudling
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Kimmo Porthan
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Jani T. Tikkanen
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Martina Müller-Nurasyid
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Katharina Schramm
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Matti Viitasalo
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Antti Jula
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Markku S. Nieminen
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Annette Peters
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Veikko Salomaa
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Lasse Oikarinen
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Richard L. Verrier
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Stefan Kääb
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - M. Juhani Junttila
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
| | - Heikki V. Huikuri
- From the Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Finland (T.V.K., J.T.T., M.J.J., H.V.H.); Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Germany (M.F.S., R.F., K.S., S.K.); German Cardiovascular Research Centre, Partner Site: Munich Heart Alliance (M.F.S., M.M.-N., A.P., S.K.); Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (B.D.N., R.L.V.); Institute of Genetic
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Tan AY, Nearing BD, Rosenberg M, Nezafat R, Josephson ME, Verrier RL. Interlead heterogeneity of R- and T-wave morphology in standard 12-lead ECGs predicts sustained ventricular tachycardia/fibrillation and arrhythmic death in patients with cardiomyopathy. J Cardiovasc Electrophysiol 2017; 28:1324-1333. [DOI: 10.1111/jce.13288] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 06/15/2017] [Accepted: 06/27/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Alex Y. Tan
- Electrophysiology Section, Division of Cardiology; Hunter Holmes McGuire VA Medical Center; Pauley Heart Center; Virginia Commonwealth University School of Medicine; Richmond VA USA
- Division of Cardiovascular Medicine; Department of Medicine, Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
| | - Bruce D. Nearing
- Division of Cardiovascular Medicine; Department of Medicine, Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
| | - Michael Rosenberg
- Division of Cardiovascular Medicine; Department of Medicine, Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
- Division of Cardiology, Department of Medicine; University of Colorado School of Medicine; Denver CO USA
| | - Reza Nezafat
- Division of Cardiovascular Medicine; Department of Medicine, Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
| | - Mark E. Josephson
- Division of Cardiovascular Medicine; Department of Medicine, Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
| | - Richard L. Verrier
- Division of Cardiovascular Medicine; Department of Medicine, Beth Israel Deaconess Medical Center; Harvard Medical School; Boston MA USA
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17
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Verrier RL, Huikuri H. Tracking interlead heterogeneity of R- and T-wave morphology to disclose latent risk for sudden cardiac death. Heart Rhythm 2017; 14:1466-1475. [PMID: 28610987 DOI: 10.1016/j.hrthm.2017.06.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Indexed: 01/10/2023]
Abstract
Sudden cardiac death (SCD) due primarily to ventricular fibrillation claims 1.5 million lives worldwide each year. In 45%-50% of cases, it is the first manifestation of underlying heart disease. Traditional risk factors including smoking, hypertension, age, sex, as well as depressed left ventricular ejection fraction lack sufficient sensitivity and specificity to forewarn of impending life-threatening arrhythmias. There has been a decades-long search for electrocardiographic (ECG) markers of SCD risk. Several interval-based indices such as QT dispersion and Tpeak-Tend interval held initial promise but ultimately yielded mixed results. Recently, the focus has been on interlead heterogeneity of R- and T-wave morphology. The new approaches have involved advanced analytical tools including vectorcardiographic techniques and second central moment analysis of QRS-aligned templates to quantify heterogeneity of depolarization and repolarization waveforms. The results of current studies appear to be robust and worthy of further exploration. This review examines the electrophysiological underpinnings of heterogeneity-based risk assessment and provides an update of clinical techniques. We also discuss future directions whereby tracking heterogeneity may help to disclose latent risk for SCD not only in ECG recordings made at rest but also during ambulatory ECG monitoring and exercise tolerance testing.
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Affiliation(s)
- Richard L Verrier
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
| | - Heikki Huikuri
- Research Unit of Internal Medicine, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
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18
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Bonomini MP, Arini PD. Modulation of spatial variance of ventricular repolarization after myocardial infarction. Biomed Signal Process Control 2017. [DOI: 10.1016/j.bspc.2017.01.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Lewek J, Ptaszynski P, Klingenheben T, Cygankiewicz I. The clinical value of T-wave alternans derived from Holter monitoring. Europace 2016; 19:529-534. [DOI: 10.1093/europace/euw292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/19/2016] [Indexed: 11/12/2022] Open
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20
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Verrier RL, Fuller H, Justo F, Nearing BD, Rajamani S, Belardinelli L. Unmasking atrial repolarization to assess alternans, spatiotemporal heterogeneity, and susceptibility to atrial fibrillation. Heart Rhythm 2016; 13:953-61. [DOI: 10.1016/j.hrthm.2015.11.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Indexed: 11/24/2022]
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21
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Kenttä TV, Nearing BD, Porthan K, Tikkanen JT, Viitasalo M, Nieminen MS, Salomaa V, Oikarinen L, Jula A, Kontula K, Newton-Cheh C, Huikuri HV, Verrier RL. Prediction of sudden cardiac death with automated high-throughput analysis of heterogeneity in standard resting 12-lead electrocardiograms. Heart Rhythm 2016; 13:713-20. [DOI: 10.1016/j.hrthm.2015.11.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Indexed: 10/22/2022]
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Affiliation(s)
- Andrew M Davis
- From the Department of Cardiology, Royal Children's Hospital, Melbourne, Victoria, Australia; Department of Pediatrics, University of Melbourne, Melbourne, Victoria, Australia; and the Murdoch Children's Research Institute, Melbourne, Victoria, Australia.
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Analysis of speed, curvature, planarity and frequency characteristics of heart vector movement to evaluate the electrophysiological substrate associated with ventricular tachycardia. Comput Biol Med 2015; 65:150-60. [PMID: 25842361 DOI: 10.1016/j.compbiomed.2015.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/18/2015] [Accepted: 03/02/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND We developed a novel method of assessing ventricular conduction using the surface ECG. METHODS Orthogonal ECGs of 81 healthy controls (age 39.0±14.2 y; 51.8% males; 94% white), were compared with iDower-transformed 12-lead ECGs (both 1000Hz), recorded in 8 patients with infarct-cardiomyopathy and sustained monomorphic ventricular tachycardia (VT) (age 68.0±7.8y, 37.5% male, mean LVEF 29±12%). Normalized speed at 10 QRS segments was calculated as the distance traveled by the heart vector along the QRS loop in three-dimensional space, divided by 1/10th of the QRS duration. Curvature was calculated as the magnitude of the derivative of the QRS loop tangent vector divided by speed. Planarity was calculated as the mean of the dihedral angles between 2 consecutive planes for all planes generated for the median beat. Orbital frequency (a scalar measure of rotation rate of the QRS vector) was calculated as a product of speed and curvature. RESULTS Mixed regression analysis showed that speed was slower [6.6 (95%CI 4.4-8.9) vs. 24.6 (95%CI 11.5-37.7)µV/ms; P<0.0001]; orbital frequency was smaller [1.4 (95%CI 1.2-1.6) vs. 6.8 (95%CI 5.4-8.1)ms(-1); P<0.0001], and planarity was larger by 3.6° (95%CI 1.4°-5.8; P=0.002) in VT cases than in healthy controls. ROC AUC for orbital frequency was 0.940 (95%CI 0.935-0.944) across all frequencies and QRS segments. ROC AUC for planarity at 70-249Hz was 0.995 (95%CI 0.985-1.00). ROC AUC for speed at 70-79Hz was 0.979 (95%CI 0.969-0.989). CONCLUSION This novel method reveals characteristic features of an abnormal electrophysiological substrate associated with VT.
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Evolution of action potential alternans in rabbit heart during acute regional ischemia. BIOMED RESEARCH INTERNATIONAL 2015; 2015:951704. [PMID: 25815342 PMCID: PMC4357036 DOI: 10.1155/2015/951704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 01/09/2015] [Accepted: 01/11/2015] [Indexed: 11/29/2022]
Abstract
This study investigates the development of the spatiotemporal pattern of action potential alternans during acute regional ischemia. Experiments were carried out in isolated Langendorff-perfused rabbit heart using a combination of optical mapping and microelectrode recordings. The alternans pattern significantly changed over time and had a biphasic character reaching maximum at 6–9 min after occlusion. Phase I (3–11 minutes of ischemia) is characterized by rapid increase in the alternans magnitude and expansion of the alternans territory. Phase I is followed by gradual decline of alternans (Phase II) in both magnitude and territory. During both phases we observed significant beat-to-beat variations of the optical action potential amplitude (OAPA) alternans. Simultaneous microelectrode recordings from subepicardial and subendocardial layers showed that OAPA alternans coincided with intramural 2 : 1 conduction blocks. Our findings are consistent with the modeling studies predicting that during acute regional ischemia alternans can be driven by 2 : 1 conduction blocks in the ischemic region.
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Verrier RL, Malik M. Quantitative T-wave alternans analysis for guiding medical therapy: an underexploited opportunity. Trends Cardiovasc Med 2014; 25:201-13. [PMID: 25541329 DOI: 10.1016/j.tcm.2014.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/09/2014] [Accepted: 10/09/2014] [Indexed: 11/18/2022]
Abstract
Reducing the toll of sudden cardiac death (SCD) remains a major challenge in cardiology, as it is the leading cause of adult mortality in the industrially developed world, claiming 310,000 lives annually in the United States alone. The main contemporary noninvasive index of cardiovascular risk, left ventricular ejection fraction (LVEF), has not proved adequately reliable, as the majority of individuals who die suddenly have relatively preserved cardiac mechanical function. Monitoring of T-wave alternans (TWA), a beat-to-beat fluctuation in ST-segment or T-wave morphology, is an attractive approach to risk stratification on both scientific and clinical grounds, as this ECG phenomenon has been shown using the FDA-cleared Spectral and Modified Moving Average methods to assess risk for cardiovascular mortality including SCD in studies enrolling >12,000 individuals with depressed or preserved LVEF. The evidence supporting TWA as a therapeutic target is reviewed.
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Affiliation(s)
- Richard L Verrier
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA.
| | - Marek Malik
- St. Paul׳s Cardiac Electrophysiology, University of London, and Imperial College, London, United Kingdom
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26
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Bonatti R, Silva AFG, Batatinha JAP, Sobrado LF, Machado AD, Varone BB, Nearing BD, Belardinelli L, Verrier RL. Selective late sodium current blockade with GS-458967 markedly reduces ischemia-induced atrial and ventricular repolarization alternans and ECG heterogeneity. Heart Rhythm 2014; 11:1827-35. [DOI: 10.1016/j.hrthm.2014.06.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Indexed: 12/19/2022]
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Nearing BD, Verrier RL. Multilead template-derived residua of surface ECGS for quantitative assessment of arrhythmia risk. Ann Noninvasive Electrocardiol 2014; 20:273-81. [PMID: 25236344 DOI: 10.1111/anec.12205] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Contemporary electrocardiographic (ECG) markers including ventricular ectopy and arrhythmias have not proved reliable in risk assessment for life-threatening arrhythmias. METHODS We developed the "Multilead ECG Template-Derived Residua" approach to remove intrinsic morphologic differences and allow calculation of pathologic ECG heterogeneities among spatially separated leads. Prediction by R-wave and T-wave heterogeneity (RWH, TWH) analysis was tested in simulated and clinical ECGs. RESULTS An enabling description of the Residua algorithm is provided. Simulated ECGs with but not without Residua produced a linear relationship (correlation coefficient r(2) = 0.999) between input and output RWH and TWH values. In heart failure patients, Residua disclosed a marked crescendo in RWH from 164.1 ± 33.1 at baseline to 299.8 ± 54.5 μV and TWH from 134.5 ± 20.6 at baseline to 239.2 ± 37.0 μV at 30-45 minutes before the arrhythmia (both, P < 0.05), which remained elevated until arrhythmia onset. Without Residua, mean RWH and TWH were elevated at 1061.0 ± 222.9 and 882.5 ± 375.2 μV, respectively, throughout the recording and were not different prior to ventricular tachycardia onset. CONCLUSIONS Calculation of ECG-template derived Residua provides a highly accurate means for assessing arrhythmia risk from standard ECGs. Potential widespread applications include resting diagnostic 12-lead, ambulatory, and exercise ECGs, electrophysiologic study laboratory recordings, and implantable devices.
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Affiliation(s)
- Bruce D Nearing
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard-Thorndike Electrophysiology Institute, Harvard Medical School, Boston, MA
| | - Richard L Verrier
- Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard-Thorndike Electrophysiology Institute, Harvard Medical School, Boston, MA
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28
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Uchimura-Makita Y, Nakano Y, Tokuyama T, Fujiwara M, Watanabe Y, Sairaku A, Kawazoe H, Matsumura H, Oda N, Ikanaga H, Motoda C, Kajihara K, Oda N, Verrier RL, Kihara Y. Time-domain T-wave alternans is strongly associated with a history of ventricular fibrillation in patients with Brugada syndrome. J Cardiovasc Electrophysiol 2014; 25:1021-1027. [PMID: 24761970 DOI: 10.1111/jce.12441] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 04/10/2014] [Accepted: 04/18/2014] [Indexed: 01/27/2023]
Abstract
AIMS T-wave alternans (TWA) is an indicator of vulnerability to ventricular arrhythmias and is useful for predicting sudden cardiac death (SCD) in patients with various structural heart diseases. We evaluated whether high levels of time-domain TWA on ambulatory ECG (AECG) are associated with a history of ventricular fibrillation (VF) in Brugada syndrome (BrS) patients. METHODS AND RESULTS We examined the associations among VF history, family history of SCD, spontaneous type 1 electrocardiogram (ECG), late potentials, VF induction by programmed electrical stimulation, and TWA in 45 BrS patients (44 males; mean age, 45 ± 15 years). TWA analyzed from 24-h AECG recordings using the modified moving average method was positive in 13 of 43 patients (30%). Patients with a history of VF had a significantly higher incidence of a positive TWA test (82% vs. 13%; P < 0.001) and spontaneous type 1 ECG (92% vs. 38%; P = 0.007) than those without VF history. Multivariate analysis indicated that positive TWA (OR 7.217; 95% CI 2.503-35.504; P = 0.002) and spontaneous type 1 ECG (OR 5.530; 95% CI 1.651-34.337; P = 0.020) were closely associated with VF history. Spontaneous type 1 ECG had high sensitivity (92%) but low specificity (63%). Positive TWA was a reliable marker with high sensitivity and specificity (82% and 88%, respectively). CONCLUSION Elevated time-domain TWA on AECG confirms arrhythmia risk in symptomatic BrS patients without the need for provocative stimuli.
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Affiliation(s)
- Yuko Uchimura-Makita
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Yukiko Nakano
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takehito Tokuyama
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Mai Fujiwara
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoshikazu Watanabe
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Akinori Sairaku
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hiroshi Kawazoe
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hiroya Matsumura
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Nozomu Oda
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hiroki Ikanaga
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Chikaaki Motoda
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kenta Kajihara
- Division of Cardiovascular Medicine, Higasihiroshima Medical Center, Hiroshima, Japan
| | - Noboru Oda
- Division of Cardiovascular Medicine, Hiroshima City Asa Hospital, Hiroshima, Japan
| | - Richard L Verrier
- Division of Cardiovascular Medicine, Harvard-Thorndike Electrophysiology Institute, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, USA
| | - Yasuki Kihara
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Merchant FM, Sayadi O, Moazzami K, Puppala D, Armoundas AA. T-wave alternans as an arrhythmic risk stratifier: state of the art. Curr Cardiol Rep 2014; 15:398. [PMID: 23881581 DOI: 10.1007/s11886-013-0398-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Microvolt level T-wave alternans (MTWA), a phenomenon of beat-to-beat variability in the repolarization phase of the ventricles, has been closely associated with an increased risk of ventricular tachyarrhythmic events (VTE) and sudden cardiac death (SCD) during medium- and long-term follow-up. Recent observations also suggest that heightened MTWA magnitude may be closely associated with short-term risk of impending VTE. At the subcellular and cellular level, perturbations in calcium transport processes likely play a primary role in the genesis of alternans, which then secondarily lead to alternans of action potential morphology and duration (APD). As such, MTWA may play a role not only in risk stratification but also more fundamentally in the pathogenesis of VTE. In this paper, we outline recent advances in understanding the pathogenesis of MTWA and also the utility of T-wave alternans testing for clinical risk stratification. We also highlight emerging clinical applications for MTWA.
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Affiliation(s)
- Faisal M Merchant
- Cardiology Division, Emory University School of Medicine, Atlanta, GA, USA
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30
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Merchant FM, Sayadi O, Puppala D, Moazzami K, Heller V, Armoundas AA. A translational approach to probe the proarrhythmic potential of cardiac alternans: a reversible overture to arrhythmogenesis? Am J Physiol Heart Circ Physiol 2013; 306:H465-74. [PMID: 24322612 DOI: 10.1152/ajpheart.00639.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Electrocardiographic alternans, a phenomenon of beat-to-beat alternation in cardiac electrical waveforms, has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death (SCD). In the clinical setting, a positive microvolt T-wave alternans test has been associated with a heightened risk of arrhythmic mortality and SCD during medium- and long-term follow-up. However, rather than merely being associated with an increased risk for SCD, several lines of preclinical and clinical evidence suggest that cardiac alternans may play a causative role in generating the acute electrophysiological substrate necessary for the onset of ventricular arrhythmias. Deficiencies in Ca(2+) transport processes have been implicated in the genesis of alternans at the subcellular and cellular level and are hypothesized to contribute to the conditions necessary for dispersion of refractoriness, wave break, reentry, and onset of arrhythmia. As such, detecting acute surges in alternans may provide a mechanism for predicting the impending onset of arrhythmia and opens the door to delivering upstream antiarrhythmic therapies. In this review, we discuss the preclinical and clinical evidence to support a causative association between alternans and acute arrhythmogenesis and outline the potential clinical implications of such an association.
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Affiliation(s)
- Faisal M Merchant
- Cardiology Division, Emory University School of Medicine, Atlanta, Georgia; and
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31
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Sur S, Han L, Tereshchenko LG. Comparison of sum absolute QRST integral, and temporal variability in depolarization and repolarization, measured by dynamic vectorcardiography approach, in healthy men and women. PLoS One 2013; 8:e57175. [PMID: 23451181 PMCID: PMC3579786 DOI: 10.1371/journal.pone.0057175] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 01/17/2013] [Indexed: 11/28/2022] Open
Abstract
Background Recently we showed the predictive value of sum absolute QRST integral (SAI QRST) and repolarization lability for risk stratification of sudden cardiac death (SCD) in heart failure patients. The goal of this study was to compare SAI QRST and metrics of depolarization and repolarization variability in healthy men and women. Methods Orthogonal ECGs were recorded at rest for 10 minutes in 160 healthy men and women (mean age 39.6±14.6, 80 men). Mean spatial TT′ angle, and normalized variances of T loop area, of spatial T vector amplitude, of QT interval and Tpeak-Tend area were measured for assessment of repolarization lability. Normalized variances of spatial QRS vector and QRS loop area characterized variability of depolarization. In addition, variability indices (VI) were calculated to adjust for normalized heart rate variance. SAI QRST was measured as the averaged arithmetic sum of areas under the QRST curve. Results Men were characterized by shorter QTc (430.3±21.7 vs. 444.7±22.2 ms; P<0.0001) and larger SAI QRST (282.1±66.7 vs.204.9±58.5 mV*ms; P<0.0001). Repolarization lability negatively correlated with spatial T vector amplitude. Adjusted by normalized heart rate variance, QT variability index was significantly higher in women than in men (−1.54±0.38 vs. −1.70±0.33; P = 0.017). However, in multivariate logistic regression after adjustment for body surface area, QTc, and spatial T vector amplitude, healthy men had 1.5–3 fold higher probability of having larger repolarization lability, as compared to healthy women (T vector amplitude variability index odds ratio 3.88(95%CI 1.4–11.1; P = 0.012). Conclusions Healthy men more likely than women have larger repolarization lability.
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Affiliation(s)
- Sanjoli Sur
- Whiting School of Engineering, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Lichy Han
- Whiting School of Engineering, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Larisa G. Tereshchenko
- The Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
- * E-mail:
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32
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Low doses of ranolazine and dronedarone in combination exert potent protection against atrial fibrillation and vulnerability to ventricular arrhythmias during acute myocardial ischemia. Heart Rhythm 2013; 10:121-7. [DOI: 10.1016/j.hrthm.2012.09.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Indexed: 12/19/2022]
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33
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Shusterman V. Spatial heterogeneity of electrical restitution as a predictor of ventricular tachyarrhythmias: a lumped-parameter approach. J Am Heart Assoc 2012; 1:e002949. [PMID: 23130173 PMCID: PMC3487361 DOI: 10.1161/jaha.112.002949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Vladimir Shusterman
- School of Medicine, Division of Cardiology, University of Pittsburgh Pittsburgh, PA
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34
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Nearing BD, Mittleman MA, Josephson ME, Verrier RL, Wellenius GA, Burger AJ. Response to Letter Regarding Article, “Crescendo in Depolarization and Repolarization Heterogeneity Heralds Development of Ventricular Tachycardia in Hospitalized Patients With Decompensated Heart Failure”. Circ Arrhythm Electrophysiol 2012. [DOI: 10.1161/circep.112.971952] [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: 11/16/2022]
Affiliation(s)
- Bruce D. Nearing
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | | | - Mark E. Josephson
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Richard L. Verrier
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Gregory A. Wellenius
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, Brown University, Providence RI
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35
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Madias JE. Letter by Madias Regarding Article, “Crescendo in Depolarization and Repolarization Heterogeneity Heralds Development of Ventricular Tachycardia in Hospitalized Patients With Decompensated Heart Failure”. Circ Arrhythm Electrophysiol 2012; 5:e78; author reply e79. [DOI: 10.1161/circep.111.970020] [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: 11/16/2022]
Affiliation(s)
- John E. Madias
- Mount Sinai School of Medicine, New York University, New York, NY, Division of Cardiology, Elmhurst Hospital Center, New York, NY
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