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"T wave alternans" OR "MTWA"

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https://www.readbyqxmd.com/read/28346324/t-wave-alternans-and-long-qt-syndrome
#1
Rebecca S Isserman, Allan F Simpao, Alan Jay Schwartz, Matthew F Pearsall
No abstract text is available yet for this article.
March 27, 2017: Anesthesiology
https://www.readbyqxmd.com/read/28339622/augmented-qrs-notching-and-macroscopic-t-wave-alternans-preceding-polymorphic-ventricular-tachycardia-in-a-patient-with-electrical-storm
#2
Shingo Minatoguchi, Nobuhiro Takasugi, Tomoki Kubota, Hiroaki Ushikoshi, Kazuhiko Nishigaki, Shinya Minatoguchi
No abstract text is available yet for this article.
February 17, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28339589/the-clinical-value-of-t-wave-alternans-derived-from-holter-monitoring
#3
Joanna Lewek, Pawel Ptaszynski, Thomas Klingenheben, Iwona Cygankiewicz
Microvolt-level T-wave alternans (TWA) assessed by spectral method during an exercise stress test has been widely studied for risk stratification. Several studies have documented the association of a positive TWA with total mortality and arrhythmic events. Nevertheless, the need to achieve an elevated and stabilized heart rate resulting in a considerable proportion of indeterminate test results constitutes one of the main limitations of this method. It is well recognized that arrhythmic events may be triggered not only by physical but also by mental stress and are not necessarily associated with exercise...
October 6, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28324970/development-of-data-acquisition-components-for-simultaneous-recording-of-3d-epicardial-and-surface-ecg-signals-in-the-langendorff-perfusion-apparatus
#4
Ryan Wade Selby, Anup Jonchhe, Chen Kaplan, Coeli M Lopes, Behnaz Ghoraani
Sudden Cardiac Death (SCD) claims 7 million lives per year. The importance of myocardial electrogram (EGM) repolarization alternans and surface electrocardiogram (ECG) T-wave alternans is gaining traction for understanding the underlying SCD mechanisms. However, the relationship between the 3D spatial distribution of myocardial EGMs and surface ECG with respect to SCD has yet to be investigated. To make this happen, a modified data acquisition system has been developed and fabricated in conjunction with the Langendorff perfusion system to enable simultaneous recording and analysis of the 3D spatial distribution of myocardial EGMs and the surface ECG...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28284506/sudden-cardiac-death-the-role-of-imaging
#5
Pieter van der Bijl, Victoria Delgado, Jeroen J Bax
Sudden cardiac death (SCD) is defined as "a non-traumatic, unexpected, fatal event occurring within one hour of the onset of symptoms in an apparently healthy subject", and it causes a fifth of all deaths worldwide. It often occurs in individuals not previously known with cardiac disease, which makes prevention challenging. The mechanism underlying SCD is thought to be a trigger (e.g. ischemia) acting upon a substrate (e.g. scar), causing a lethal arrhythmia. Primary prevention refers to patients at high risk of SCD and secondary prevention to those who have had an aborted episode of SCD...
March 6, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28268303/effects-and-underlying-mechanisms-of-refractory-period-pacing-on-repolarization-dynamics-in-the-human-heart
#6
Diogo Santos, Michele Orini, Xin Zhou, Alfonso Bueno-Orovio, Ben Hanson, Peter Taggart, Martin Hayward, Blanca Rodriguez, Pier Lambiase
Repolarization alternans is related to the initiation of life threatening cardiac arrhythmias. Experimental and computational studies suggest that the abolishment of alternans using dynamic pacing protocols may prevent abnormal heart rhythms. In a recent animal study, refractory period pacing (RPP) on every other beat has shown promising results in alternans reduction. However, the cellular mechanisms underlying this therapy and its efficiency in human patients remain unclear. In this study, in vivo unipolar electrograms acquired during RPP from 240 epicardial sites from one patient were analysed...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227084/development-of-data-acquisition-components-for-simultaneous-recording-of-3d-epicardial-and-surface-ecg-signals-in-the-langendorff-perfusion-apparatus
#7
Ryan Wade Selby, Anup Jonchhe, Chen Kaplan, Coeli M Lopes, Behnaz Ghoraani, Ryan Wade Selby, Anup Jonchhe, Chen Kaplan, Coeli M Lopes, Behnaz Ghoraani, Chen Kaplan, Behnaz Ghoraani, Anup Jonchhe, Coeli M Lopes, Ryan Wade Selby
Sudden Cardiac Death (SCD) claims 7 million lives per year. The importance of myocardial electrogram (EGM) repolarization alternans and surface electrocardiogram (ECG) T-wave alternans is gaining traction for understanding the underlying SCD mechanisms. However, the relationship between the 3D spatial distribution of myocardial EGMs and surface ECG with respect to SCD has yet to be investigated. To make this happen, a modified data acquisition system has been developed and fabricated in conjunction with the Langendorff perfusion system to enable simultaneous recording and analysis of the 3D spatial distribution of myocardial EGMs and the surface ECG...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226462/effects-and-underlying-mechanisms-of-refractory-period-pacing-on-repolarization-dynamics-in-the-human-heart
#8
Diogo Santos, Michele Orini, Xin Zhou, Alfonso Bueno-Orovio, Ben Hanson, Peter Taggart, Martin Hayward, Blanca Rodriguez, Pier Lambiase, Diogo Santos, Michele Orini, Xin Zhou, Alfonso Bueno-Orovio, Ben Hanson, Peter Taggart, Martin Hayward, Blanca Rodriguez, Pier Lambiase, Ben Hanson, Diogo Santos, Martin Hayward, Pier Lambiase, Alfonso Bueno-Orovio, Blanca Rodriguez, Michele Orini, Xin Zhou, Peter Taggart
Repolarization alternans is related to the initiation of life threatening cardiac arrhythmias. Experimental and computational studies suggest that the abolishment of alternans using dynamic pacing protocols may prevent abnormal heart rhythms. In a recent animal study, refractory period pacing (RPP) on every other beat has shown promising results in alternans reduction. However, the cellular mechanisms underlying this therapy and its efficiency in human patients remain unclear. In this study, in vivo unipolar electrograms acquired during RPP from 240 epicardial sites from one patient were analysed...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28102901/risk-of-arrhythmic-death-in-ischemic-heart-disease-a-prospective-controlled-observer-blind-risk-stratification-over-10%C3%A2-years
#9
Thomas Pezawas, André Diedrich, David Robertson, Robert Winker, Bernhard Richter, Li Wang, Herwig Schmidinger
BACKGROUND: Risk of arrhythmic death is considered highest in ischemic heart disease with severe left ventricular ejection fraction (LVEF) reduction. Non-invasive testing should improve decision-making of prophylactic defibrillator (ICD) implantation. DESIGN: We enrolled 120 patients with ischemic heart disease and LVEF < 50% and 30 control subjects without ischemic heart disease and normal LVEF. An initial assessment, a second assessment after 3 years and a final follow-up comprised of pharmacological baroreflex testing (BRS), short-term spectral [low-frequency (LF) to high-frequency (HF) ratio] and long-term time-domain analysis of heart rate variability (SDNN), exercise Microvolt T-wave alternans (MTWA) and others...
March 2017: European Journal of Clinical Investigation
https://www.readbyqxmd.com/read/27916321/exercise-induced-quantitative-microvolt-t-wave-alternans-in-hypertrophic-cardiomyopathy
#10
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)...
March 2017: 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
#11
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
#12
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
#13
RANDOMIZED CONTROLLED TRIAL
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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...
November 2016: Journal of Electrocardiology
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