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Bernd R Gardill, Ricardo E Rivera-Acevedo, Ching-Chieh Tung, Mark Okon, Lawrence P McIntosh, Filip Van Petegem
Voltage-gated sodium channels (NaV ) are responsible for the rapid depolarization of many excitable cells. They readily inactivate, a process where currents diminish after milliseconds of channel opening. They are also targets for a multitude of disease-causing mutations, many of which have been shown to affect inactivation. A cluster of disease mutations, linked to Long-QT and Brugada syndromes, is located in a C-terminal EF-hand like domain of NaV 1.5, the predominant cardiac sodium channel isoform. Previous studies have suggested interactions with the III-IV linker, a cytosolic element directly involved in inactivation...
March 14, 2018: Scientific Reports
Mengye Li, Karan R Chadda, Gareth D K Matthews, Celia M Marr, Christopher L-H Huang, Kamalan Jeevaratnam
Exercising horses uniquely accommodate 7-8-fold increases in heart rate (HR). The present experiments for the first time analysed the related adaptations in action potential (AP) restitution properties recorded by in vivo telemetric electrocardiography from Thoroughbred horses. The horses were subjected to a period of acceleration from walk to canter. The QRS durations, and QT and TQ intervals yielded AP conduction velocities, AP durations (APDs) and diastolic intervals respectively. From these, indices of active, λ = QT/(QRS duration), and resting, λ0 = TQ/(QRS duration), AP wavelengths were calculated...
2018: PloS One
Salma I Patel, Michael J Ackerman, Fadi E Shamoun, Jeffrey B Geske, Steve R Ommen, William T Love, Stephen S Cha, Johan M Bos, Steven J Lester
INTRODUCTION: Risk assessment for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) remains complex. The goal of this study was to assess electrocardiogram (ECG)-derived risk factors on SCD in a large HCM population Methods: Retrospective review of adults with HCM evaluated at Mayo Clinic, Rochester, MN from 1 December 2002 to 31 December 2012 was performed. Data inclusive of ECG and 24-hour ambulatory Holter monitor were assessed. SCD events were documented by ventricular fibrillation (VF) noted on implantable cardioverter defibrillator (ICD), or appropriate VT or VF-terminating ICD shock...
March 7, 2018: Acta Cardiologica
Jesus Mates, Irene Mademont-Soler, Bernat Del Olmo, Carles Ferrer-Costa, Monica Coll, Alexandra Pérez-Serra, Ferran Picó, Catarina Allegue, Anna Fernandez-Falgueras, Patricia Álvarez, Raquel Yotti, Maria Angeles Espinosa, Georgia Sarquella-Brugada, Sergi Cesar, Ester Carro, Josep Brugada, Elena Arbelo, Pablo Garcia-Pavia, Mar Borregan, Eduardo Tizzano, Amador López-Granados, Francisco Mazuelos, Aranzazu Díaz de Bustamante, Maria Teresa Darnaude, José Ignacio González-Hevia, Felícitas Díaz-Flores, Francisco Trujillo, Anna Iglesias, Francisco Fernandez-Aviles, Oscar Campuzano, Ramon Brugada
Several studies have identified copy number variants (CNVs) as responsible for cardiac diseases associated with sudden cardiac death (SCD), but very few exhaustive analyses in large cohorts of patients have been performed, and they have been generally focused on a specific SCD-related disease. The aim of the present study was to screen for CNVs the most prevalent genes associated with SCD in a large cohort of patients who suffered sudden unexplained death or had an inherited cardiac disease (cardiomyopathy or channelopathy)...
March 6, 2018: European Journal of Human Genetics: EJHG
Valentina Kutyifa, Usama Daimee, Scott McNitt, Bronislava Polonsky, Charles Lowenstein, Kris Cutter, Coeli Lopes, Wojciech Zareba, Arthur J Moss
BACKGROUND: A comprehensive report on the clinical course of the three major genotypes of the long QT syndrome (LQTS) in a large U.S. patient cohort is lacking. METHODS: Our study consisted of 1,923 U.S. subjects from the Rochester-based LQTS Registry with genotype-positive LQT1 (n = 879), LQT2 (n = 807), and LQT3 (n = 237). We evaluated the risk of a first cardiac event (syncope, aborted cardiac arrest, or sudden cardiac death, whichever occurred first) from birth through age 50 years...
March 5, 2018: Annals of Noninvasive Electrocardiology
Kaori Kohzuma, Kouki Hikosaka
Non-photochemical quenching (NPQ) is the most important photoprotective system in higher plants. NPQ can be divided into several steps according to the timescale of relaxation of chlorophyll fluorescence after reaching a steady state (i.e., the fast phase, qE; middle phase, qZ or qT; and slow phase, qI). The dissipation of excess energy as heat during the xanthophyll cycle, a large component of NPQ, is detectable during the fast to middle phase (sec to min). Although thermal dissipation is primarily investigated using indirect methods such as chlorophyll a fluorescence measurements, such analyses require dark adaptation or the application of a saturating pulse during measurement, making it difficult to continuously monitor this process...
February 28, 2018: Biochemical and Biophysical Research Communications
C M Mak, S Pl Chen, N S Mok, W K Siu, H Hc Lee, C K Ching, P T Tsui, N C Fong, Y P Yuen, W T Poon, C Y Law, Y K Chong, Y W Chan, T C Yung, K Yy Fan, C W Lam
INTRODUCTION: Hereditary channelopathies and cardiomyopathies are potentially lethal and are clinically and genetically heterogeneous, involving at least 90 genes. Genetic testing can provide an accurate diagnosis, guide treatment, and enable cascade screening. The genetic basis among the Hong Kong Chinese population is largely unknown. We aimed to report on 28 unrelated patients with positive genetic findings detected from January 2006 to December 2015. METHODS: Sanger sequencing was performed for 28 unrelated patients with a clinical diagnosis of channelopathies or cardiomyopathies, testing for the following genes: KCNQ1, KCNH2, KCNE1, KCNE2, and SCN5A, for long QT syndrome; SCN5A for Brugada syndrome; RYR2 for catecholaminergic polymorphic ventricular tachycardia; MYH7 and MYBPC3 for hypertrophic cardiomyopathy; LMNA for dilated cardiomyopathy; and PKP2 and DSP for arrhythmogenic right ventricular dysplasia/cardiomyopathy...
March 2, 2018: Hong Kong Medical Journal, Xianggang Yi Xue za Zhi
Rezvan Enteshari Najafabadi, Nasrin Kazemipour, Abolghasem Esmaeili, Siamak Beheshti, Saeed Nazifi
Background: Superparamagnetic iron oxide nanoparticles (SPION) have been largely considered for numerous applications in biomedicine such as magnetic resonance imaging, hyperthermia, cell tracking, anticancer treatment, and targeted delivery of drugs or genes. However, they may have side effects such body weight loss. Quercetin (QT), a strong antioxidant and free radical scavenger and a natural flavonoid, has a wide range of biological and therapeutic effects. In this study, the effect of QT on prevention of weight loss due to the using of SPION has been investigated...
2018: Advanced Biomedical Research
Timothy R Larsen, Jedediah McMunn, Hala Ahmad, Soufian T AlMahameed
A 32-year-old male developed recurrent ventricular tachycardia after taking mega doses of loperamide and famotidine in order to experience an opiate-like euphoric effect. He was taking up to 200 mg of loperamide and multiple doses of famotidine each day. He developed palpitations and syncope. Electrocardiography demonstrated ventricular tachycardia and QT interval prolongation (corrected QT interval was 597 ms). He was diagnosed with loperamide-induced QT prolongation resulting in incessant ventricular tachycardia...
February 17, 2018: Drug Safety—Case Reports
M Vornanen, K Aktan-Collan, N Hallowell, H Konttinen, H Kääriäinen, A Haukkala
Lowered costs of genomic sequencing facilitate analyzing large segments of genetic data. Ethical debate has focused on whether and what kind of incidental or secondary findings (SFs) to report, and how to obtain valid informed consent. However, people's support needs after receiving SFs have received less attention. We explored Finnish adults' perspectives on reporting genetic SFs. In this qualitative study which included four focus group discussions (N = 23) we used four vignette letters, each reporting a genetic SF predisposing to a different disease: familial hypercholesterolemia, long QT syndrome, Lynch syndrome, and Li-Fraumeni syndrome...
January 16, 2018: Journal of Community Genetics
Přemysl Mladěnka, Lenka Applová, Jiří Patočka, Vera Marisa Costa, Fernando Remiao, Jana Pourová, Aleš Mladěnka, Jana Karlíčková, Luděk Jahodář, Marie Vopršalová, Kurt J Varner, Martin Štěrba
Cardiovascular diseases are a leading cause of morbidity and mortality in most developed countries of the world. Pharmaceuticals, illicit drugs, and toxins can significantly contribute to the overall cardiovascular burden and thus deserve attention. The present article is a systematic overview of drugs that may induce distinct cardiovascular toxicity. The compounds are classified into agents that have significant effects on the heart, blood vessels, or both. The mechanism(s) of toxic action are discussed and treatment modalities are briefly mentioned in relevant cases...
January 5, 2018: Medicinal Research Reviews
Olivier Huttin, Christine Selton-Suty, Clément Venner, Jean-Baptiste Vilain, Pierre Rochecongar, Etienne Aliot
BACKGROUND: High-level physical training induces cardiac structural and functional changes, including 12-lead electrocardiogram modifications. OBJECTIVES: The purpose of this cross-sectional longitudinal study was to establish a quantitative electrocardiographic profile in highly trained football players. Initial and serial annual electrocardiogram monitoring over subsequent years allowed us to investigate the long-term effects of exercise on cardiac conduction and electrophysiological remodelling...
December 21, 2017: Archives of Cardiovascular Diseases
Susanne Markendorf, Thomas Felix Lüscher, Jin-Hong Gerds-Li, Felix Schönrath, Christian Marc Schmied
BACKGROUND: The impact of postural changes on various electrocardiography (ECG) charac-teristics has only been assessed in a few small studies. This large prospective trial was con-ducted to confirm or refute preliminary data and add important results with immediate impact on daily clinical practice. METHODS: ECGs in supine and upright position from 1028 patients were analyzed. Evaluation was made according to changes in T-wave vector and direction, ST-segment deviation, heart rate, QT interval and QTc interval was performed...
December 14, 2017: Cardiology Journal
Andreas Reusser, Steffen Blum, Stefanie Aeschbacher, Lucien Eggimann, Peter Ammann, Paul Erne, Giorgio Moschovitis, Marcello Di Valentino, Dipen Shah, Jürg Schläpfer, Samuel Manser, Tobias Reichlin, Michael Kühne, Christian Sticherling, Stefan Osswald, David Conen
BACKGROUND: A longer QTc interval has been associated with more adverse cardiovascular events and death in the general population. Little evidence is available on these relationships among patients with atrial fibrillation (AF). METHODS: We performed a prospective observational multicenter cohort study of 1413 patients with AF. A resting 12‑lead electrocardiogram (ECG) was performed at baseline. QT interval was corrected for heart rate using the Bazett formula (QTc)...
February 1, 2018: International Journal of Cardiology
Judith Brouillette, Stanley Nattel
Drugs that act on mental state, generally termed "psychoactive agents," are among the most widely used medications in medicine. Psychoactive agents can affect the cardiovascular system and must be used carefully to avoid negative cardiovascular consequences. In the present article we review the potential adverse cardiovascular consequences of psychoactive medications and provide suggestions for practical approaches to avoiding them. We consider adverse reactions in terms of: (1) arrhythmias (particularly acquired long QT syndrome); (2) blood pressure; (3) ventricular function; (4) effect on risk factors; (5) teratogenicity; and (6) drug interactions...
December 2017: Canadian Journal of Cardiology
Qin Qin, Jianqing Li, Yinggao Yue, Chengyu Liu
R-peak detection is crucial in electrocardiogram (ECG) signal analysis. This study proposed an adaptive and time-efficient R-peak detection algorithm for ECG processing. First, wavelet multiresolution analysis was applied to enhance the ECG signal representation. Then, ECG was mirrored to convert large negative R-peaks to positive ones. After that, local maximums were calculated by the first-order forward differential approach and were truncated by the amplitude and time interval thresholds to locate the R-peaks...
2017: Journal of Healthcare Engineering
Stephen Bacchi, Ivana Chim, Philippe Kramer, Ronald B Postuma
BACKGROUND: Domperidone is a proposed treatment of orthostatic hypotension (OH) in Parkinson's disease (PD). However, domperidone use in PD is tempered by concerns regarding QT prolongation and ventricular tachyarrhythmia and sudden cardiac death (VT/SCD). OBJECTIVE: The aim is to identify peer-reviewed studies in which either (1) the effect of domperidone on blood pressure in patients with PD, or (2) the adverse effects associated with domperidone use in PD patients has been reported...
2017: Journal of Parkinson's Disease
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
Jaehee V Shim, Bryan Chun, Johan G C van Hasselt, Marc R Birtwistle, Jeffrey J Saucerman, Eric A Sobie
Tyrosine kinase inhibitors (TKIs) are highly potent cancer therapeutics that have been linked with serious cardiotoxicity, including left ventricular dysfunction, heart failure, and QT prolongation. TKI-induced cardiotoxicity is thought to result from interference with tyrosine kinase activity in cardiomyocytes, where these signaling pathways help to control critical processes such as survival signaling, energy homeostasis, and excitation-contraction coupling. However, mechanistic understanding is limited at present due to the complexities of tyrosine kinase signaling, and the wide range of targets inhibited by TKIs...
2017: Frontiers in Physiology
Amnah Y Bdier, Saleh Al-Ghamdi, Prashant K Verma, Khalid Dagriri, Bandar Alshehri, Omamah A Jiman, Sherif E Ahmed, Arthur A M Wilde, Zahurul A Bhuiyan, Jumana Y Al-Aama
BACKGROUND: One of the most common primary cardiac arrhythmia syndromes is autosomal dominant long QT syndrome, type 1 (LQT1), chiefly caused by mono-allelic mutations in the KCNQ1 gene. Bi-allelic mutations in the KCNQ1 gene are causal to Jervell and Lange-Nielsen syndrome (JLNS), characterized by severe and early-onset arrhythmias with prolonged QTc interval on surface ECG and sensorineural deafness. Occasionally, bi-allelic mutations in KCNQ1 are also found in patients without any deafness, referred to as autosomal recessive long QT syndrome, type 1 (AR LQT1)...
September 2017: Molecular Genetics & Genomic Medicine
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