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"T wave alternans" OR "MTWA"

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https://www.readbyqxmd.com/read/27916321/exercise-induced-quantitative-microvolt-t-wave-alternans-in-hypertrophic-cardiomyopathy
#1
Murillo de Oliveira Antunes, Nelson Samesima, Horacio Gomes Pereira Filho, Afonso Yoshikiro Matsumoto, Richard L Verrier, Carlos Alberto Pastore, Edmundo Arteaga-Fernández, Charles Mady
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)...
October 28, 2016: Journal of Electrocardiology
https://www.readbyqxmd.com/read/27879279/heart-rate-turbulence-is-a-powerful-predictor-of-cardiac-death-and-ventricular-arrhythmias-in-postmyocardial-infarction-and-heart-failure-patients-a-systematic-review-and-meta-analysis
#2
Marcello Disertori, Michela Masè, Marta Rigoni, Giandomenico Nollo, Flavia Ravelli
BACKGROUND: Heart rate turbulence (HRT) has been proposed as a candidate marker of altered autonomic tone, and some studies showed its prognostic value for both cardiac death (CD) and sudden death. Nevertheless, HRT is not currently used in the clinical practice. METHODS AND RESULTS: We performed a systematic review and meta-analysis of the predictive value of HRT for the end points of total mortality, CD, and fatal and nonfatal ventricular arrhythmias in postacute myocardial infarction and heart failure patients...
December 2016: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/27872443/microvolt-t-wave-alternans-testing-is-abnormal-both-in-left-and-right-sided-pathology
#3
EDITORIAL
Katarzyna Mizia-Stec
No abstract text is available yet for this article.
November 2016: Anatolian Journal of Cardiology
https://www.readbyqxmd.com/read/27778458/t-wave-alternans-heart-rate-turbulence-and-ventricular-ectopy-in-standard-versus-daily-hemodialysis-results-from-the-fhn-daily-trial
#4
Rachel M Kaplan, Charles A Herzog, Brett Larive, Haris Subacius, Bruce D Nearing, Richard Verrier, Rod S Passman
BACKGROUND: Hemodialysis (HD) patients are at high risk of sudden cardiac death (SCD). HD 6-times/week (6x/wk) may reduce SCD risk compared to usual 3-times/week HD (3x/wk) by mechanisms unknown. T-wave alternans (TWA), heart rate turbulence (HRT), and ventricular ectopy (VE) are elevated in HD patients, but their response to 6x/wk HD has not been assessed. METHODS: Baseline and 1-year Holter recordings were analyzed from enrollees in the Frequent Hemodialysis Network Daily Trial, a randomized trial comparing 3x/wk to 6x/wk in 245 chronic HD patients...
November 2016: Annals of Noninvasive Electrocardiology
https://www.readbyqxmd.com/read/27777148/eleclazine-an-inhibitor-of-the-cardiac-late-sodium-current-is-superior-to-flecainide-in-suppressing-catecholamine-induced-ventricular-tachycardia-and-t-wave-alternans-in-an-intact-porcine-model
#5
Danilo Bacic, Juliana Saran Carneiro, Afonso Alves Bento, Bruce D Nearing, Sridharan Rajamani, Luiz Belardinelli, Richard L Verrier
BACKGROUND: The capacity of catecholamines to induce ventricular tachycardia (VT) is well documented. OBJECTIVE: The effectiveness of the novel cardiac late sodium inhibitor eleclazine in suppressing catecholamine-induced VT in a large animal model was compared with that of flecainide. METHODS: In 13 closed-chest anesthetized Yorkshire pigs, spontaneous VT and surges in T-wave alternans (TWA) level measured using the Modified Moving Average method were induced by epinephrine (2...
October 21, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/27765387/t-wave-alternans-an-ominous-marker-for-malignant-cardiac-arrhythmias
#6
Gurunath Parale, Chinmay Parale
No abstract text is available yet for this article.
October 17, 2016: European Journal of Internal Medicine
https://www.readbyqxmd.com/read/27702850/traditional-and-novel-electrocardiographic-conduction-and-repolarization-markers-of-sudden-cardiac-death
#7
Gary Tse, Bryan P Yan
Sudden cardiac death, frequently due to ventricular arrhythmias, is a significant problem globally. Most affected individuals do not arrive at hospital in time for medical treatment. Therefore, there is an urgent need to identify the most-at-risk patients for insertion of prophylactic implantable cardioverter defibrillators. Clinical risk markers derived from electrocardiography are important for this purpose. They can be based on repolarization, including corrected QT (QTc) interval, QT dispersion (QTD), interval from the peak to the end of the T-wave (Tpeak - Tend), (Tpeak - Tend)/QT, T-wave alternans (TWA), and microvolt TWA...
October 4, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/27665532/multi-window-detection-for-p-wave-in-electrocardiograms-based-on-bilateral-accumulative-area
#8
Riqing Chen, Yingsong Huang, Jian Wu
BACKGROUND AND OBJECTIVE: P-wave detection is one of the most challenging aspects in electrocardiograms (ECGs) due to its low amplitude, low frequency, and variable waveforms. This work introduces a novel multi-window detection method for P-wave delineation based on the bilateral accumulative area. METHOD: The bilateral accumulative area is calculated by summing the areas covered by the P-wave curve with left and right sliding windows. The onset and offset of a positive P-wave correspond to the local maxima of the area detector...
September 15, 2016: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/27660578/surface-electrocardiogram-predictors-of-sudden-cardiac-arrest
#9
REVIEW
Samy A Abdelghani, Todd M Rosenthal, Daniel P Morin
BACKGROUND: Heart disease is a major cause of death in industrialized nations, with approximately 50% of these deaths attributable to sudden cardiac arrest. If patients at high risk for sudden cardiac arrest can be identified, their odds of surviving fatal arrhythmias can be significantly improved through prophylactic implantable cardioverter defibrillator placement. This review summarizes the current knowledge pertaining to surface electrocardiogram (ECG) predictors of sudden cardiac arrest...
2016: Ochsner Journal
https://www.readbyqxmd.com/read/27616659/involvement-of-mitochondrial-permeability-transition-pore-mptp-in-cardiac-arrhythmias-evidence-from-cyclophilin-d-knockout-mice
#10
Richard Gordan, Nadezhda Fefelova, Judith K Gwathmey, Lai-Hua Xie
In the present study, we have used a genetic mouse model that lacks cyclophilin D (CypD KO) to assess the cardioprotective effect of mitochondrial permeability transition pore (mPTP) inhibition on Ca(2+) waves and Ca(2+) alternans at the single cell level, and cardiac arrhythmias in whole-heart preparations. The protonophore carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) caused mitochondrial membrane potential depolarization to the same extent in cardiomyocytes from both WT and CypD KO mice, however, cardiomyocytes from CypD KO mice exhibited significantly less mPTP opening than cardiomyocytes from WT mice (p<0...
December 2016: Cell Calcium
https://www.readbyqxmd.com/read/27597389/does-manual-t-wave-window-adjustment-affect-microvolt-t-wave-alternans-results-in-patients-with-structural-heart-disease
#11
Tharmathai Ramanan, Kathir Balakumaran, Sairekha Ravichandran, Stephen J Ganocy, Ganiyu Oshodi, Otto Costantini, Mary Dettmer, Peter J Leo, Elizabeth S Kaufman
INTRODUCTION: Microvolt T-wave alternans (MTWA) analysis can identify patients at low risk of sudden cardiac death who might not benefit from an implantable cardioverter-defibrillator (ICD). Current spectral methodology for performing MTWA analysis may "miss" part of the T-wave in patients with QT prolongation. The value of T-wave window adjustment in patients with structural heart disease has not been studied. METHODS: We assembled MTWA data from 5 prior prospective studies including 170 patients with reduced left ventricular ejection fraction, adjusted the T-wave window to include the entire T-wave, and reanalyzed MTWA...
August 4, 2016: Journal of Electrocardiology
https://www.readbyqxmd.com/read/27554424/electrocardiographic-predictors-of-mortality-and-sudden-cardiac-death-in-patients-with-end-stage-renal-disease-on-hemodialysis
#12
Jonathan W Waks, Larisa G Tereshchenko, Rulan S Parekh
Patients with end stage renal disease (ESRD) on hemodialysis experience a high incidence of cardiovascular mortality, and sudden cardiac death (SCD) accounts for approximately 25% of all deaths in this patient population. Despite this high risk of SCD, many non-invasive SCD risk stratification tools that are frequently applied to other patient populations (such as those with prior myocardial infarction and reduced left ventricular systolic function) may be less useful markers of increased SCD risk in ESRD. Improved SCD risk stratification tools for use specifically in patients on hemodialysis are therefore necessary to optimally target use of primary prevention interventions aimed at decreasing SCD incidence...
July 28, 2016: Journal of Electrocardiology
https://www.readbyqxmd.com/read/27508328/laparoscopic-approach-for-thermoablation-microwave-in-the-treatment-of-hepatocellular-carcinoma-a-single-center-experience
#13
Salvatore Gruttadauria, Duilio Pagano, Alessandro Tropea, Davide Cintorino, Luisa Castellana, Pasquale Bonsignore, Calogero Ricotta, Gaetano Piccolo, Giovanni Vizzini, Angelo Luca
BACKGROUND: The surgical therapy of choice for hepatocellular carcinoma (HCC) is liver transplantation (LT) or hepatic resection, although only a small percentage of patients can undergo these procedures. Microwave thermal ablation (MWTA) can be an effective alternative treatment for HCC that complicates a cirrhotic liver disease, either as a final procedure or for downstaging patients on the waiting list for LT, or in combination with resective surgery to achieve oncological radicality...
October 2016: Journal of Laparoendoscopic & Advanced Surgical Techniques. Part A
https://www.readbyqxmd.com/read/27489981/beat-to-beat-t-wave-alternans-detection-using-the-ensemble-empirical-mode-decomposition-method
#14
Muhammad A Hasan, Vijay S Chauhan, Sridhar Krishnan
BACKGROUND: T-wave alternans (TWA) is defined as a consistent variation in the repolarization morphology that repeats on every other beat. This study aimed to evaluate beat-to-beat TWA detection using the Ensemble EMD (EEMD) method. METHOD: A total of 108 recordings of standard 12-lead ECGs of 69 healthy subjects (17 females, 42±18 years; 52 males, 40±13 years) and 39 cardiac-condition patients (ischemic cardiomyopathy; ICM and dilated cardiomyopathy; DCM) with left ventricular ejection fractions (LVEF) ≤40% were studied...
October 1, 2016: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/27467316/usefulness-of-microvolt-t-wave-alternans-for-predicting-outcome-in-patients-with-chagas-disease-with-implantable-cardioverter-defibrillators
#15
Marco Paulo Tomaz Barbosa, Manoel Otávio da Costa Rocha, Elson Santos Neto, Fernando Vieira Brandão, Federico Lombardi, Antonio Luiz Pinho Ribeiro
BACKGROUND: Chagas disease (ChD) may lead to life-threatening heart disease, including malignant ventricular arrhythmias. The use of implantable cardioverter defibrillators (ICDs) has become the main therapeutic strategy for secondary prevention of SCD in Chagas disease (ChD). Microvolt T-wave alternans (MTWA) is a direct measure of ventricular repolarization instability and has emerged as a potentially useful way of determining arrhythmia vulnerability. However, this methodology has not been evaluated in patients with ChD...
November 1, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/27450311/baseline-elevation-and-reduction-in-cardiac-electrical-instability-assessed-by-quantitative-t-wave-alternans-in-patients-with-drug-resistant-epilepsy-treated-with-vagus-nerve-stimulation-in-the-aspiresr-e-36-trial
#16
Richard L Verrier, Bruce D Nearing, Bryan Olin, Paul Boon, Steven C Schachter
OBJECTIVE: Reports of cardiac arrhythmias and cardiac pathology at postmortem examination of patients with epilepsy suggest a possible cardiac component of risk for sudden unexpected death in epilepsy (SUDEP). T-wave alternans (TWA) is an established marker of cardiac electrical instability and risk for sudden death in patients with cardiovascular disease. We determined the TWA level before vagus nerve stimulation (VNS) system implantation and subsequently the effect of VNS on TWA in patients with drug-resistant epilepsy...
September 2016: Epilepsy & Behavior: E&B
https://www.readbyqxmd.com/read/27403292/microvolt-t-wave-alternans-where-are-we-now
#17
Aapo L Aro, Tuomas V Kenttä, Heikki V Huikuri
Microvolt T-wave alternans (TWA), characterised as beat-to-beat fluctuation of T-wave amplitude and morphology, is an electrophysiological phenomenon associated clinically with impending ventricular arrhythmias and is an important marker of arrhythmia risk. Currently, two main methods for the detection of TWA exist, namely, the spectral method and the time-domain modified moving average method; both are discussed in this review. Microvolt TWA has been associated with cardiovascular mortality and sudden cardiac death in several clinical studies involving >14,000 subjects with reduced as well as preserved left ventricular function...
May 2016: Arrhythmia & Electrophysiology Review
https://www.readbyqxmd.com/read/27344495/microvolt-t-wave-alternans-amplifies-spatial-dispersion-of-repolarization-in-human-subjects-with-ischemic-cardiomyopathy
#18
Tilak Pasala, Mary Dettmer, Peter J Leo, Kenneth R Laurita, Elizabeth S Kaufman
INTRODUCTION: In experimental models, spatial dispersion of repolarization (DOR) due to discordant cellular alternans predisposes to ventricular fibrillation. To test the hypothesis that microvolt T-wave alternans (MTWA) in humans causes spatial DOR, we measured Tpeak-Tend interval (Tpe) and Tpe/QT ratio, electrocardiographic indices of spatial DOR. METHODS: Mean Tpe and Tpe/QT were compared in ischemic cardiomyopathy patients with positive and negative MTWA studies...
September 2016: Journal of Electrocardiology
https://www.readbyqxmd.com/read/27336310/electrophysiology-of-heart-failure-using-a-rabbit-model-from-the-failing-myocyte-to-ventricular-fibrillation
#19
Aditya V S Ponnaluri, Luigi E Perotti, Michael Liu, Zhilin Qu, James N Weiss, Daniel B Ennis, William S Klug, Alan Garfinkel
Heart failure is a leading cause of death, yet its underlying electrophysiological (EP) mechanisms are not well understood. In this study, we use a multiscale approach to analyze a model of heart failure and connect its results to features of the electrocardiogram (ECG). The heart failure model is derived by modifying a previously validated electrophysiology model for a healthy rabbit heart. Specifically, in accordance with the heart failure literature, we modified the cell EP by changing both membrane currents and calcium handling...
June 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27317981/inhibition-of-the-cardiac-late-sodium-current-with-eleclazine-protects-against-ischemia-induced-vulnerability-to-atrial-fibrillation-and-reduces-atrial-and-ventricular-repolarization-abnormalities-in-the-absence-and-presence-of-concurrent-adrenergic-stimulation
#20
Fernanda Justo, Henrique Fuller, Bruce D Nearing, Sridharan Rajamani, Luiz Belardinelli, Richard L Verrier
BACKGROUND: Myocardial ischemia carries dual risk for initiating atrial and ventricular arrhythmias that can be exacerbated by adrenergic stimulation. OBJECTIVE: The purpose of this study was to investigate whether selective inhibition of the cardiac late sodium current (INa) with eleclazine decreases susceptibility to ischemia-induced atrial fibrillation (AF) and atrial and ventricular repolarization abnormalities before and after epinephrine infusion. METHODS: In chloralose-anesthetized, open-chest, male Yorkshire pigs (n = 12), atrial and ventricular ischemia was induced by partial occlusion of the left circumflex coronary artery proximal segment to reduce flow by 75%...
September 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
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