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T wave alternans

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https://www.readbyqxmd.com/read/29777559/utility-of-heart-rate-turbulence-and-t-wave-alternans-to-assess-risk-for-re-admission-and-cardiac-death-in-hospitalized-heart-failure-patients
#1
Shinya Yamada, Akiomi Yoshihisa, Yu Sato, Takamasa Sato, Masashi Kamioka, Takashi Kaneshiro, Masayoshi Oikawa, Atsushi Kobayashi, Hitoshi Suzuki, Takafumi Ishida, Yasuchika Takeishi
BACKGROUND: Heart failure (HF) patients have a higher risk of recurrent HF and cardiac death, and electrical remodeling is considered to be an important factor for HF progression. The present study aimed to validate the utility of electrocardiogram and Holter monitoring for the risk stratification of HF patients. METHODS: Our study comprised 215 patients (144 males, mean age 62 years) who had been hospitalized due to acute decompensated HF. Electrocardiogram (QRS duration and QTc interval) and 24-hour Holter monitoring (heart rate variability, heart rate turbulence and T-wave alternans [TWA]) were performed in stable condition before discharge...
May 18, 2018: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/29753687/istaroxime-a-positive-inotropic-agent-devoid-of-proarrhythmic-properties-in-sensitive-chronic-atrioventricular-block-dogs
#2
Alexandre Bossu, Amée Kostense, Henriette D M Beekman, Marien J C Houtman, Marcel A G van der Heyden, Marc A Vos
Current inotropic agents in heart failure therapy associate with low benefit and significant adverse effects, including ventricular arrhythmias. Istaroxime, a novel Na+ /K+ -transporting ATPase inhibitor, also stimulates SERCA2a activity, which would confer improved inotropic and lusitropic properties with less proarrhythmic effects. We investigated hemodynamic, electrophysiological and potential proarrhythmic and antiarrhythmic effects of istaroxime in control and chronic atrioventricular block (CAVB) dogs sensitive to drug-induced Torsades de Pointes arrhythmias (TdP)...
May 10, 2018: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
https://www.readbyqxmd.com/read/29739399/the-roles-of-mid-myocardial-and-epicardial-cells-in-t-wave-alternans-development-a-simulation-study
#3
D Janusek, J Svehlikova, J Zelinka, W Weigl, R Zaczek, G Opolski, M Tysler, R Maniewski
BACKGROUND: The occurrence of T-wave alternans in electrocardiographic signals was recently linked to susceptibility to ventricular arrhythmias and sudden cardiac death. Thus, by detecting and comprehending the origins of T-wave alternans, it might be possible to prevent such events. RESULTS: Here, we simulated T-wave alternans in a computer-generated human heart model by modulating the action potential duration and amplitude during the first part of the repolarization phase...
May 8, 2018: Biomedical Engineering Online
https://www.readbyqxmd.com/read/29723261/microvolt-t-wave-alternans-and-autonomic-nervous-system-parameters-can-be-helpful-in-the-identification-of-low-arrhythmic-risk-patients-with-ischemic-left-ventricular-systolic-dysfunction
#4
Ludmiła Daniłowicz-Szymanowicz, Damian Kaufmann, Katarzyna Rozwadowska, Maciej Kempa, Ewa Lewicka, Grzegorz Raczak
INTRODUCTION: The role of implantable cardioverter-defibrillator (ICD) placement in the primary prevention of sudden cardiac death (SCD) in all consecutive patients with left ventricular ejection fraction (LVEF) ≤ 35% is still a matter of hot debate due to the fact that the population of these patients is highly heterogeneous in terms of the SCD risk. Nevertheless, reduced LVEF is still the only established criterion during qualification of patients for ICD implantation in the primary prevention of SCD, therefore identification of persons with particularly high risk among patients with LVEF ≤35% is currently of lesser importance...
2018: PloS One
https://www.readbyqxmd.com/read/29684090/predictors-of-poor-outcome-in-patients-with-pulmonary-arterial-hypertension-a-single-center-study
#5
Emilia Stepnowska, Ewa Lewicka, Alicja Dąbrowska-Kugacka, Ludmiła Daniłowicz-Szymanowicz, Paweł Zagożdżon, Rafał Kamiński, Zuzanna Lewicka-Potocka, Paweł Miękus, Dariusz Kozłowski, Wojciech Potocki, Grzegorz Raczak
OBJECTIVES: Pulmonary arterial hypertension (PAH) is a rare disorder with unfavorable prognosis despite implementation of specific PAH-oriented therapy. The aim of the study was to define predictors of poor prognosis in patients from one center treated according to the Polish National Health Fund program. PATIENTS AND METHODS: Forty-seven consecutive patients (30 women; aged 39±17 years) with PAH diagnosis were enrolled to the study. Clinical assessment, laboratory measurements, electrocardiogram, echocardiography, 6-minute walk test, 24-hour Holter monitoring, cardiopulmonary exercise test and microvolt T-wave alternans test were performed during routine visits...
2018: PloS One
https://www.readbyqxmd.com/read/29461965/post-ventricular-premature-contraction-phase-correction-improves-the-predictive-value-of-average-t-wave-alternans-in-ambulatory-ecg-recordings
#6
Alba Martin-Yebra, Violeta Monasterio, Iwona Cygankiewicz, Antoni Bayes-de-Luna, Enrico G Caiani, Pablo Laguna, Juan Pablo Martinez
OBJECTIVE: We proposed and evaluated a method for correcting possible phase shifts provoked by the presence of ventricular premature contractions (VPCs) for a better assessment of T-wave alternans (TWA).  Methods: First, we synthesized ECG signals with artificial TWA in the presence of different noise sources. Then, we assessed the prognostic value for sudden cardiac death (SCD) of the long-term average of TWA amplitude (the index of average alternans, ) in ambulatory ECG signals from congestive heart failure (CHF) and evaluated whether it is sensitive to the presence of VPCs...
March 2018: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/29427819/significance-of-t-wave-inversion-triggered-by-spontaneous-atrial-premature-beats-in-patients-with-long-qt-syndrome
#7
Nobuhiro Takasugi, Mieko Takasugi, Hiroko Goto, Takashi Kuwahara, Takashi Nakashima, Tomoki Kubota, Hiromitsu Kanamori, Masanori Kawasaki, Kazuhiko Nishigaki, Shinya Minatoguchi, Richard L Verrier
BACKGROUND: In patients with the long QT syndrome (LQTS), a sudden increase in heart rate can cause T-wave alternans (TWA) with beat-to-beat alternating polarity of T wave. We hypothesized that LQTS patients at high risk for torsades de pointes (TdP) may exhibit momentary atrial or sinoatrial premature beat-induced T-wave inversion (APB-TWI). OBJECTIVE: The purpose of this study was to assess the association of APB-TWI with TdP history and with microvolt TWA. METHODS: Twenty-four-hour continuous 12-lead electrocardiograms (ECGs) were recorded in 18 healthy subjects and 39 consecutive patients with LQTS types 1 (n = 21), 2 (n = 4), 3 (n = 4), and unidentified (n = 10)...
February 7, 2018: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29377142/mechanisms-linking-t-wave-alternans-to-spontaneous-initiation-of-ventricular-arrhythmias-in-rabbit-models-of-long-qt-syndrome
#8
Weiqing Liu, Tae Yun Kim, Xiaodong Huang, Michael B Liu, Gideon Koren, Bum-Rak Choi, Zhilin Qu
KEY POINTS: T-wave alternans (TWA) and T-wave lability (TWL) are precursors of ventricular arrhythmias in long QT syndrome; however, the mechanistic link remains to be clarified. Computer simulations show that action potential duration (APD) prolongation and slowed heart rates promote APD alternans and chaos, manifesting as TWA and TWL, respectively. Regional APD alternans and chaos can exacerbate pre-existing or induce de novo APD dispersion, which combines with enhanced ICa,L to result in premature ventricular complexes (PVCs) originating from the APD gradient region...
April 15, 2018: Journal of Physiology
https://www.readbyqxmd.com/read/29356998/real-time-closed-loop-diastolic-interval-control-prevents-cardiac-alternans-in-isolated-whole-rabbit-hearts
#9
Kanchan Kulkarni, Steven W Lee, Ryan Kluck, Elena G Tolkacheva
Cardiac alternans, a beat-to-beat alternation in action potential duration (APD), can lead to fatal arrhythmias. During periodic pacing, changes in diastolic interval (DI) depend on subsequent changes in APD, thus enhancing cardiac instabilities through a 'feedback' mechanism. Recently, an anti-arrhythmic Constant DI pacing protocol was proposed and shown to be effective in suppressing alternans in 0D and 1D in silico studies. However, previous experimental validation of Constant DI pacing in the heart has been unsuccessful due to the spatio-temporal complexity of 2D cardiac tissue and the technical challenges in its real-time implementation...
April 2018: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/29194862/a-case-report-is-mexiletine-usage-effective-in-the-shortening-of-qtc-interval-and-improving-the-t-wave-alternans-in-timothy-syndrome
#10
Gulhan Tunca Sahin, Yakup Ergul
Timothy syndrome (TS) is a multisystemic disease that occurs because of a mutation in CACN1C gene and is characterized by prolonged QT interval. Mexiletine is a Class 1B antiarrhythmic drug that causes the disappearance of T-wave alternans by shortening QTc and peak-to-end of the T wave. It may block the development of torsades de pointes in a prolonged QT. This study presented the case of a patient diagnosed with TS and had a cardiac arrest history, prolonged QT, and T-wave alternans. After mexiletine treatment, the QTc interval shortened and T-wave alternans disappeared...
November 30, 2017: Annals of Noninvasive Electrocardiology
https://www.readbyqxmd.com/read/29183619/non-sustained-microvolt-level-t-wave-alternans-in-congenital-long-qt-syndrome-types-1-and-2
#11
Jovil A Kannampuzha, Prasanna Sengodan, Sravani Avula, Bartholomew White, Stephen J Ganocy, Peter J Leo, Elizabeth S Kaufman
BACKGROUND: Patients with long QT syndrome (LQTS) are predisposed to polymorphic ventricular tachycardia (VT) during adrenergic stimulation. Microvolt T-wave alternans (MTWA) is linked to vulnerability to VT in structural heart disease. The prevalence of non-sustained MTWA (NS-MTWA) in LQTS is unknown. METHODS: 31 LQT1, 42 LQT2, and 80 controls underwent MTWA testing during exercise. MTWA tests were classified per standardized criteria, and re-analyzed according to the modified criteria to account for NS-MTWA...
March 2018: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29126547/microvolt-t-wave-alternans-monitoring-in-a-patient-with-levofloxacin-induced-torsade-de-pointes
#12
Yuki Sahashi, Nobuhiro Takasugi, Genki Naruse, Tomoki Kubota, Kazuhiko Nishigaki, Shinya Minatoguchi
We present the case of a 62-year-old woman with levofloxacin-induced Torsade de Pointes, in whom microvolt T-wave alternans was measured during acute hospitalization and when QT interval was dynamically changing, illustrating a means for monitoring proarrhythmia.
January 2018: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29108464/electrocardiographic-alterations-in-patients-consuming-synthetic-cannabinoids
#13
Hayriye M Ozturk, Mehmet Erdogan, Yakup Alsancak, Mikail Yarlioglues, Mustafa Duran, M Hamid Boztas, Sani N Murat, Selcuk Ozturk
INTRODUCTION: The aim of this study was to investigate the electrocardiographic parameters in patients consuming synthetic cannabinoids. METHODS: Thirty-five patients who were consuming synthetic cannabinoids were enrolled to the study, prospectively. The control group included 35 healthy age and sex-matched volunteers. The standard 12-lead surface electrocardiograms of the study population were recorded. P maximum (Pmax ), P minimum (Pmin ), P wave dispersion, interatrial duration, P wave area in D2 derivation, abnormal P terminal force in V1 derivation, heart rate, QT interval, corrected QT, QT dispersion, PR interval duration and macrovolt T-wave alternans were evaluated by two experienced cardiologists...
March 2018: Journal of Psychopharmacology
https://www.readbyqxmd.com/read/29037423/unique-ecg-presentations-and-clinical-management-of-a-symptomatic-lqt2-female-carrying-a-novel-de-novo-kcnh2-mutation
#14
Chunlin Yin, Ping Zhang, Jing Yang, Li Zhang
A 26-year-old woman, 12 days in postpartum, developed recurrent syncope and cardiac arrest. Her ECG revealed QT-prolongation associated with LQT2-specific T-U wave patterns, T wave alternans, long QT-dependent torsade de pointes (TdP) and ventricular fibrillation (VF). She also had intermittent LBBB (80bpm) on alternate beats and RBBB at sinus tachycardia (113bpm). Family genotyping revealed a novel de novo missense mutation G604C of KCNH2. Propranolol slowed heart rate and further prolonged QT interval (610ms) that caused TdP recurrence...
January 2018: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29020031/sudden-cardiac-death-and-pump-failure-death-prediction-in-chronic-heart-failure-by-combining-ecg-and-clinical-markers-in-an-integrated-risk-model
#15
Julia Ramírez, Michele Orini, Ana Mincholé, Violeta Monasterio, Iwona Cygankiewicz, Antonio Bayés de Luna, Juan Pablo Martínez, Pablo Laguna, Esther Pueyo
BACKGROUND: Sudden cardiac death (SCD) and pump failure death (PFD) are common endpoints in chronic heart failure (CHF) patients, but prevention strategies are different. Currently used tools to specifically predict these endpoints are limited. We developed risk models to specifically assess SCD and PFD risk in CHF by combining ECG markers and clinical variables. METHODS: The relation of clinical and ECG markers with SCD and PFD risk was assessed in 597 patients enrolled in the MUSIC (MUerte Súbita en Insuficiencia Cardiaca) study...
2017: PloS One
https://www.readbyqxmd.com/read/28964198/a-multichannel-decision-level-fusion-method-for-t-wave-alternans-detection
#16
Changrong Ye, Xiaoping Zeng, Guojun Li, Chenyuan Shi, Xin Jian, Xichuan Zhou
Sudden cardiac death (SCD) is one of the most prominent causes of death among patients with cardiac diseases. Since ventricular arrhythmia is the main cause of SCD and it can be predicted by T wave alternans (TWA), the detection of TWA in the body-surface electrocardiograph (ECG) plays an important role in the prevention of SCD. But due to the multi-source nature of TWA, the nonlinear propagation through thorax, and the effects of the strong noises, the information from different channels is uncertain and competitive with each other...
September 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28918212/an-%C3%AE-glucosidase-inhibitor-could-reduce-t-wave-alternans-in-type-2-diabetes-patients
#17
Kazuo Eguchi, Takahiro Komori, Toshinobu Saito, Satoshi Hoshide, Kazuomi Kario
BACKGROUND: We tested the hypothesis that an alpha-glucosidase inhibitor (α-GI), miglitol, is effective in protecting the cardiovascular system in type 2 diabetes mellitus (T2DM). METHODS: We studied 19 hospitalized heart disease patients with T2DM in whom we performed continuous glucose monitoring, Holter electrocardiogram, and ambulatory blood pressure (BP) monitoring simultaneously for 48h. The α-GI miglitol was administered for half of the study period by a cross-over fashion...
January 2018: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28916174/evaluation-of-beat-to-beat-ventricular-repolarization-lability-from-standard-12-lead-ecg-during-acute-myocardial-ischemia
#18
Salah S Al-Zaiti, Mohammad Alrawashdeh, Christian Martin-Gill, Clifton Callaway, David Mortara, Jan Nemec
BACKGROUND: Acute myocardial ischemia is a common cause of ventricular arrhythmias, yet recent ECG methods predicting susceptibility to ventricular tachyarrhythmia have not been fully evaluated during spontaneous ischemia. We sought to evaluate the clinical utility of alternans and non-alternans components of repolarization variability from the standard 10-second 12-lead ECG signals to risk stratify patients with acute chest pain. METHODS: We enrolled consecutive, non-traumatic, chest pain patients transported through Emergency Medical Services (EMS) to three tertiary care hospitals with cardiac catheterization lab capabilities in Pittsburgh, PA...
November 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28871362/electrocardiographic-markers-of-appropriate-implantable-cardioverter-defibrillator-therapy-in-young-people-with-congenital-heart-diseases
#19
Dunia Bárbara Benítez Ramos, Michel Cabrera Ortega, Jesús Castro Hevia, Margarita Dorantes Sánchez, Ailema Amelia Alemán Fernández, Osmin Castañeda Chirino, Marlenis Cruz Cardentey, Frank Martínez López, Roylan Falcón Rodríguez
Implantable cardioverter-defibrillators (ICDs) are increasingly utilized in patients with congenital heart disease (CHD). Prediction of the occurrence of shocks is important if improved patient selection is desired. The electrocardiogram (ECG) has been the first-line tool predicting the risk of sudden death, but data in CHD patients are lacking. We aim to evaluate the predictive value of electrocardiographic markers of appropriate therapy of ICD in young people with CHD. We conducted a prospective, longitudinal study, in twenty-six CHD patients (mean age 24...
December 2017: Pediatric Cardiology
https://www.readbyqxmd.com/read/28783809/macroscopic-t-wave-alternans-a-red-flag-for-code-blue
#20
Peter K Moore, Katie E Raffel, Isaac R Whitman
No abstract text is available yet for this article.
October 1, 2017: JAMA Internal Medicine
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