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https://www.readbyqxmd.com/read/29050844/monitoring-the-corrected-qt-in-the-acute-care-setting-a-comparison-of-the-12%C3%A2-lead-electrocardiogram-and-bedside-monitor
#1
James A Chenoweth, Aaron M Hougham, Daniel K Colby, Jonathan B Ford, Jordan Sandhu, Timothy E Albertson, Mark E Sutter
INTRODUCTION: Prolongation of the QT interval is a well-recognized complication associated with many commonly used medications. Emergency Department monitoring of the corrected QT (QTc) both before and after medication administration is typically performed using the 12‑lead electrocardiogram (ECG). The purpose of this study is to compare the QTc reported on the 12‑lead ECG to that reported by single brand of bedside monitor. METHODS: A convenience sample of emergency department patients over the age of 18 undergoing bedside monitoring and who had an ECG ordered by their treating physician were enrolled...
October 7, 2017: American Journal of Emergency Medicine
https://www.readbyqxmd.com/read/29046645/computational-cardiac-modeling-reveals-mechanisms-of-ventricular-arrhythmogenesis-in-long-qt-syndrome-type-8-cacna1c-r858h-mutation-linked-to-ventricular-fibrillation
#2
Jieyun Bai, Kuanquan Wang, Yashu Liu, Yacong Li, Cuiping Liang, Gongning Luo, Suyu Dong, Yongfeng Yuan, Henggui Zhang
Functional analysis of the L-type calcium channel has shown that the CACNA1C R858H mutation associated with severe QT interval prolongation may lead to ventricular fibrillation (VF). This study investigated multiple potential mechanisms by which the CACNA1C R858H mutation facilitates and perpetuates VF. The Ten Tusscher-Panfilov (TP06) human ventricular cell models incorporating the experimental data on the kinetic properties of L-type calcium channels were integrated into one-dimensional (1D) fiber, 2D sheet, and 3D ventricular models to investigate the pro-arrhythmic effects of CACNA1C mutations by quantifying changes in intracellular calcium handling, action potential profiles, action potential duration restitution (APDR) curves, dispersion of repolarization (DOR), QT interval and spiral wave dynamics...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29046643/trigger-vs-substrate-multi-dimensional-modulation-of-qt-prolongation-associated-arrhythmic-dynamics-by-a-herg-channel-activator
#3
Michael A Colman, Erick A Perez Alday, Arun V Holden, Alan P Benson
Background: Prolongation of the QT interval of the electrocardiogram (ECG), underlain by prolongation of the action potential duration (APD) at the cellular level, is linked to increased vulnerability to cardiac arrhythmia. Pharmacological management of arrhythmia associated with QT prolongation is typically achieved through attempting to restore APD to control ranges, reversing the enhanced vulnerability to Ca(2+)-dependent afterdepolarisations (arrhythmia triggers) and increased transmural dispersion of repolarisation (arrhythmia substrate) associated with APD prolongation...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29045448/interferon-free-therapy-with-direct-acting-antivirals-for-hcv-hiv-1-co-infected-japanese-patients-with-inherited-bleeding-disorders
#4
Haruka Uemura, Kunihisa Tsukada, Daisuke Mizushima, Takahiro Aoki, Koji Watanabe, Ei Kinai, Katsuji Teruya, Hiroyuki Gatanaga, Yoshimi Kikuchi, Masaya Sugiyama, Masashi Mizokami, Shinichi Oka
INTRODUCTION: Almost 30 years ago, about 30% of Japanese hemophiliacs became infected with HIV-1 and hepatitis C virus (HCV) after receiving contaminated blood products. While several studies have reported the high efficacy and safety of direct acting antivirals (DAA) in HIV-1 co-infected patients, such data are limited in hemophiliacs. METHODS: We conducted a single-center, open-label study involving 27 Japanese patients (median age; 45 years) with inherited bleeding disorders who were co-infected with HCV/HIV-1...
2017: PloS One
https://www.readbyqxmd.com/read/29044094/evaluation-of-tp-e-interval-tp-e-qt-ratio-and-tp-e-qtc-ratio-in-patients-with-mitral-valve-stenosis-before-and-after-balloon-valvuloplasty
#5
Muhammet Dural, Kadir Uğur Mert, Kemal İskenderov
OBJECTIVE: Sympathetic activity increases in patients with mitral stenosis (MS). The association between prolonged Tpeak-Tend (Tp-e) interval and increased sympathetic activity has been demonstrated. This study aimed to evaluate Tp-e interval, Tp-e/QT ratio, and Tp-e/corrected QT interval (QTc) ratio in patients with MS before and after balloon valvuloplasty. METHODS: Thirty patients with severe MS and 30 sex-, body mass index-, and and age-matched healthy control subjects were enrolled...
October 13, 2017: Anatolian Journal of Cardiology
https://www.readbyqxmd.com/read/29042382/drugs-and-life-threatening-ventricular-arrhythmia-risk-results-from-the-dare-study-cohort
#6
Abigail L Coughtrie, Elijah R Behr, Deborah Layton, Vanessa Marshall, A John Camm, Saad A W Shakir
OBJECTIVES: To establish a unique sample of proarrhythmia cases, determine the characteristics of cases and estimate the contribution of individual drugs to the incidence of proarrhythmia within these cases. SETTING: Suspected proarrhythmia cases were referred by cardiologists across England between 2003 and 2011. Information on demography, symptoms, prior medical and drug histories and data from hospital notes were collected. PARTICIPANTS: Two expert cardiologists reviewed data for 293 referred cases: 130 were included...
October 16, 2017: BMJ Open
https://www.readbyqxmd.com/read/29037423/unique-ecg-presentations-and-clinical-management-of-a-symptomatic-lqt2-female-carrying-a-novel-de-novo-kcnh2-mutation
#7
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...
August 17, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29037240/kh176-under-development-for-rare-mitochondrial-disease-a-first-in-man-randomized-controlled-clinical-trial-in-healthy-male-volunteers
#8
Saskia Koene, Edwin Spaans, Luc Van Bortel, Griet Van Lancker, Brant Delafontaine, Fabio Badilini, Julien Beyrath, Jan Smeitink
BACKGROUND: Mitochondrial disorders are a clinically, biochemically and genetically heterogeneous group of multi-system diseases, with an unmet medical need for treatment. KH176 is an orally bio-available small molecule under development for the treatment of mitochondrial(-related) diseases. The compound is a member of a new class of drugs, acting as a potent intracellular redox-modulating agent essential for the control of oxidative and redox pathologies. The aim of this randomized, placebo controlled, double-blinded phase 1 study was to test safety, tolerability and pharmacokinetics of single and multiple doses of KH176 in healthy male volunteers...
October 16, 2017: Orphanet Journal of Rare Diseases
https://www.readbyqxmd.com/read/29037160/-homozygous-and-compound-heterozygous-mutation-in-3-turkish-family-with-jervell-and-lange-nielsen-syndrome-case-reports
#9
Fahrettin Uysal, Burcu Turkgenc, Guven Toksoy, Ozlem M Bostan, Elif Evke, Oya Uyguner, Cengiz Yakicier, Hulya Kayserili, Ergun Cil, Sehime G Temel
BACKGROUND: Jervell and Lange-Nielsen syndrome (JLNS) isa recessive model of long QT syndrome which might also be related to possible hearing loss. Although the syndrome has been demonstrated to be originated from homozygous or compound heterozygous mutations in either the KCNQ1 or KCNE1 genes, additional mutations in other genetic loci should be considered, particularly in malignant course patients. CASE PRESENTATIONS: Three patients were admitted into hospital due to recurrent seizures/syncope, intrauterine and postnatal bradycardia respectively; moreover all three patients had congenital sensorineural hearing-loss...
October 16, 2017: BMC Medical Genetics
https://www.readbyqxmd.com/read/29036623/predictors-of-mortality-in-high-risk-patients-with-qt-prolongation-in-a-community-hospital
#10
Charlotte Gibbs, Jacob Thalamus, Kristian Heldal, Øystein Lunde Holla, Kristina H Haugaa, Jan Hysing
Aims: To determine predictors of mortality in patients with corrected QT interval (QTc) ≥ 500 ms in a community hospital. Methods and results: In this retrospective observational study, we searched the electrocardiogram (ECG) database at Telemark Hospital Trust, Norway, from January 2004 to December 2014. Medication, electrolyte abnormalities, and medical conditions known to prolong the QT interval were recorded. From the medical records, we assessed whether the prolonged QTc was noted by the health care providers...
October 3, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29036559/the-brisk-standing-test-for-long-qt-syndrome-in-prepubertal-school-children-defining-normal
#11
L H P M Filippini, P G Postema, K Zoubin, B J M Hermans, N A Blom, T Delhaas, A A M Wilde
Aims: Long QT syndrome (LQTS) is associated with malignant arrhythmias and sudden death from birth to advanced age. Prolongation of the QT-interval, may however be concealed on standard electrocardiograms (ECG). The brisk-standing-test (BST) was developed to guide LQTS-diagnosis and treatment in adults. We hypothesized that the BST may be used in prepubertal children to identify LQTS subjects. Accordingly, reference values for the BST should be available to prevent incorrect diagnosis and treatment of LQTS...
October 3, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29035985/qt-corrections-for-long-qt-risk-assessment-implications-for-the-preparticipation-examination
#12
David Hadley, David Hsu, David Pickham, Jonathan A Drezner, Victor F Froelicher
BACKGROUND: Because sudden cardiac death (SCD) in the young mainly occur in individuals with structurally normal hearts, improved screening techniques for detecting inherited arrhythmic diseases are needed. The QT interval is an important screening measurement; however, the criteria for detecting an abnormal QT interval are based on Bazett formula and older populations. OBJECTIVE: To define the normal upper limits for QT interval from the electrocardiograms (ECGs) of healthy young individuals, compare the major correction formula and propose new QT interval thresholds for detecting those at risk of SCD...
October 10, 2017: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
https://www.readbyqxmd.com/read/29030380/association-between-qt-interval-components-and-sudden-cardiac-death-the-aric-study-atherosclerosis-risk-in-communities
#13
Wesley T O'Neal, Matthew J Singleton, Jason D Roberts, Larisa G Tereshchenko, Nona Sotoodehnia, Lin Y Chen, Gregory M Marcus, Elsayed Z Soliman
BACKGROUND: Several reports have demonstrated that prolongation of the QT interval is associated with sudden cardiac death (SCD). However, it is unknown whether any of the components within the QT interval are responsible for its association with SCD. METHODS AND RESULTS: We examined the association of the individual QT-interval components (R-wave onset to R-peak, R-peak to R-wave end, ST-segment, T-wave onset to T-peak, and T-peak to T-wave end) with SCD in 12 241 participants (54±5...
October 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29029798/effect-of-intravenous-ondansetron-on-qtc-interval-in-children-with-gastroenteritis
#14
Robert J Hoffman, Khalid Alansari
BACKGROUND: The potential for ondansetron to cause QT prolongation and fatal dysrhythmia is well-reported, including a 2011 FDA report on the topic. Few clinical trials evaluating this phenomenon in the ED setting exist, and only one is pediatric. OBJECTIVE: We have sought to determine the effect of a standardized dose of intravenous ondansetron on the QTc duration of children under 14years of age treated for gastroenteritis-associated vomiting in a pediatric ED...
October 4, 2017: American Journal of Emergency Medicine
https://www.readbyqxmd.com/read/29021306/characterization-of-a-human-induced-pluripotent-stem-cell-derived-cardiomyocyte-model-for-the-study-of-variant-pathogenicity-validation-of-a-kcnj2-mutation
#15
Roselle Gélinas, Nabil El Khoury, Marie-A Chaix, Claudine Beauchamp, Azadeh Alikashani, Nathalie Ethier, Gabrielle Boucher, Louis Villeneuve, Laura Robb, Frédéric Latour, Blandine Mondesert, Lena Rivard, Philippe Goyette, Mario Talajic, Céline Fiset, John David Rioux
BACKGROUND: Long-QT syndrome is a potentially fatal condition for which 30% of patients are without a genetically confirmed diagnosis. Rapid identification of causal mutations is thus a priority to avoid at-risk situations that can lead to fatal cardiac events. Massively parallel sequencing technologies are useful for the identification of sequence variants; however, electrophysiological testing of newly identified variants is crucial to demonstrate causality. Long-QT syndrome could, therefore, benefit from having a standardized platform for functional characterization of candidate variants in the physiological context of human cardiomyocytes...
October 2017: Circulation. Cardiovascular Genetics
https://www.readbyqxmd.com/read/29020304/identification-of-a-targeted-and-testable-antiarrhythmic-therapy-for-long-qt-syndrome-type-2-using-a-patient-specific-cellular-model
#16
Ashish Mehta, Chrishan J A Ramachandra, Pritpal Singh, Anuja Chitre, Chong Hui Lua, Manuela Mura, Lia Crotti, Philip Wong, Peter J Schwartz, Massimiliano Gnecchi, Winston Shim
Aims: Loss-of-function mutations in the hERG gene causes long-QT syndrome type 2 (LQT2), a condition associated with reduced IKr current. Four different mutation classes define the molecular mechanisms impairing hERG. Among them, Class 2 mutations determine hERG trafficking defects. Lumacaftor (LUM) is a drug acting on channel trafficking already successfully tested for cystic fibrosis and its safety profile is well known. We hypothesize that LUM might rescue also hERG trafficking defects in LQT2 and exert anti-arrhythmic effects...
July 21, 2017: European Heart Journal
https://www.readbyqxmd.com/read/29016765/broad-antiarrhythmic-effect-of-mexiletine-in-different-arrhythmia-models
#17
Gerrit Frommeyer, Jonas Garthmann, Christian Ellermann, Dirk G Dechering, Simon Kochhäuser, Florian Reinke, Julia Köbe, Kristina Wasmer, Lars Eckardt
Aims: Experimental studies and clinical reports suggest antiarrhythmic properties of mexiletine in different arrhythmias. We aimed at investigating mexiletine in experimental models of atrial fibrillation (AF) as well as in long-QT- (LQTS) and short-QT-syndrome (SQTS). Methods and results: In 15 isolated rabbit hearts, erythromycin (300 µM) was infused for simulation of long-QT-2-syndrome. In further 13 hearts, veratridine was administered to simulate long-QT-3-syndrome...
August 1, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29016351/ameliorative-effect-of-gallic-acid-on-doxorubicin-induced-cardiac-dysfunction-in-rats
#18
Temiday O Omóbòwálé, Ademola A Oyagbemi, Ayorinde M Folasire, Temitayo O Ajibade, Ebunoluwa R Asenuga, Olumuyiwa A Adejumobi, Olufunke E Ola-Davies, Orotusin Oyetola, Gana James, Adeolu A Adedapo, Momoh A Yakubu
BACKGROUND: The use of doxorubicin (DOX) as an antineoplastic agent has been greatly limited because of the myriad of toxic sequelae associated with it. The aim of this study was to assess the protective effects of gallic acid (GA) on DOX-induced cardiac toxicity in rats. METHODS: Sixty male rats (Wistar strain) were used in this study. They were divided into six groups (A-F) each containing 10 animals. Group A was the control. Rats in Groups B, C, and D were treated with DOX at the dosage of 15 mg/kg body weight i...
October 9, 2017: Journal of Basic and Clinical Physiology and Pharmacology
https://www.readbyqxmd.com/read/28992755/drug-mediated-shortening-of-action-potentials-in-lqts2-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#19
Gary Duncan, Karl Firth, Vinoj George, Minh Duc Hoang, Andrew Staniforth, Godfrey Smith, Chris Denning
Cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSCs) are now a well-established modality for modelling genetic disorders of the heart. This is especially so for long QT syndrome (LQTS), which is caused by perturbation of ion channel function, and can lead to fainting, malignant arrhythmias and sudden cardiac death. LQTS2 is caused by mutations in KCNH2, a gene whose protein product contributes to IKr (also known as HERG), which is the predominant repolarising potassium current in CMs...
October 9, 2017: Stem Cells and Development
https://www.readbyqxmd.com/read/28986934/mechanistic-model-informed-proarrhythmic-risk-assessment-of-drugs-review-of-the-cipa-initiative-and-design-of-a-prospective-clinical-validation-study
#20
Jose Vicente, Robbert Zusterzeel, Lars Johannesen, Jay Mason, Philip Sager, Vikram Patel, Murali K Matta, Zhihua Li, Jiang Liu, Christine Garnett, Norman Stockbridge, Issam Zineh, David G Strauss
The Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative is developing and validating a mechanistic-based assessment of proarrhythmic risk of drugs. CiPA proposes to assess a drug's effect on multiple ion channels and integrate the effects in a computer model of the human cardiomyocyte to predict proarrhythmic risk. Unanticipated or missed effects will be assessed with human stem cell derived cardiomyocytes and electrocardiogram (ECG) analysis in early phase 1 clinical trials. This paper provides an overview of CiPA and the rationale and design of the CiPA phase 1 ECG validation clinical trial, which involves assessing an additional ECG biomarker (J-Tpeak) for QT prolonging drugs...
October 7, 2017: Clinical Pharmacology and Therapeutics
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