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https://www.readbyqxmd.com/read/28728690/contemporary-outcomes-in-patients-with%C3%A2-long-qt-syndrome
#1
Ram K Rohatgi, Alan Sugrue, J Martijn Bos, Bryan C Cannon, Samuel J Asirvatham, Christopher Moir, Heidi J Owen, Katy M Bos, Teresa Kruisselbrink, Michael J Ackerman
BACKGROUND: Long QT syndrome (LQTS) is a potentially lethal cardiac channelopathy with a 1% to 5% annual risk of LQTS-triggered syncope, aborted cardiac arrest, or sudden cardiac death. OBJECTIVES: This study sought to evaluate LQTS outcomes from a single center in the contemporary era. METHODS: The authors conducted a retrospective study comprising the 606 patients with LQTS (LQT1 in 47%, LQT2 in 34%, and LQT3 in 9%) who were evaluated in Mayo Clinic's Genetic Heart Rhythm Clinic from January 1999 to December 2015...
July 25, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28725320/splice-site-variants-in-the-kcnq1-and-scn5a-genes-transcript-analysis-as-a-tool-in-supporting-pathogenicity
#2
Ivone U S Leong, Philippa A Dryland, Debra O Prosser, Stella W-S Lai, Mandy Graham, Martin Stiles, Jackie Crawford, Jonathan R Skinner, Donald R Love
BACKGROUND: Approximately 75% of clinically definite long QT syndrome (LQTS) cases are caused by mutations in the KCNQ1, KCNH2 and SCN5A genes. Of these mutations, a small proportion (3.2-9.2%) are predicted to affect splicing. These mutations present a particular challenge in ascribing pathogenicity. METHODS: Here we report an analysis of the transcriptional consequences of two mutations, one in the KCNQ1 gene (c.781_782delinsTC) and one in the SCN5A gene (c.2437-5C>A), which are predicted to affect splicing...
August 2017: Journal of Clinical Medicine Research
https://www.readbyqxmd.com/read/28720088/sex-is-a-moderator-of-the-association-between-nos1ap-sequence-variants-and-qtc-in-two-long-qt-syndrome-founder-populations-a-pedigree-based-measured-genotype-association-analysis
#3
Annika Winbo, Eva-Lena Stattin, Ida Maria Westin, Anna Norberg, Johan Persson, Steen M Jensen, Annika Rydberg
BACKGROUND: Sequence variants in the NOS1AP gene have repeatedly been reported to influence QTc, albeit with moderate effect sizes. In the long QT syndrome (LQTS), this may contribute to the substantial QTc variance seen among carriers of identical pathogenic sequence variants. Here we assess three non-coding NOS1AP sequence variants, chosen for their previously reported strong association with QTc in normal and LQTS populations, for association with QTc in two Swedish LQT1 founder populations...
July 18, 2017: BMC Medical Genetics
https://www.readbyqxmd.com/read/28685698/medical-therapy-for-long-qt-syndrome
#4
George Adamos, Nicoletta Iacovidou, Theodoros Xanthos
Long QT syndrome (LQTS) is an arrhythmogenic disorder characterized by repolarization abnormalities with a propensity to cause life threatening cardiac events. The first manifestation of the syndrome may be sudden death, therefore, early diagnosis and therapy is of great importance. LQTS can be both congenital and acquired. The latter is most commonly seen in hospitalized patients and such individuals have an easily recognizable and reversible precipitating factor (electrolyte disturbances, certain drugs etc...
July 7, 2017: Mini Reviews in Medicinal Chemistry
https://www.readbyqxmd.com/read/28670758/congenital-long-qt-syndrome-and-torsade-de-pointes
#5
REVIEW
Nabil El-Sherif, Gioia Turitto, Mohamed Boutjdir
Since its initial description by Jervell and Lange-Nielsen in 1957, the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. A prolonged QT interval in the surface electrocardiogram is the sine qua non of the LQTS and is a surrogate measure of the ventricular action potential duration (APD). Congenital as well as acquired alterations in certain cardiac ion channels can affect their currents in such a way as to increase the APD and hence the QT interval. The inhomogeneous lengthening of the APD across the ventricular wall results in dispersion of APD...
July 2, 2017: Annals of Noninvasive Electrocardiology
https://www.readbyqxmd.com/read/28663329/long-qt-syndrome-and-sudden-unexpected-infant-death
#6
EDITORIAL
Chantal Van Niekerk, Barbara Ströh Van Deventer, Lorraine du Toit-Prinsloo
Long QT syndrome (LQTS) is an inheritable primary electric disease of the heart characterised by abnormally long QT intervals and a propensity to develop atrial and ventricular tachyarrhythmias. It is caused by an inherited channelopathy responsible for sudden cardiac death in individuals with structurally normal hearts. Long QT syndrome can present early in life, and some studies suggest that it may be associated with up to 20% of sudden unexplained infant death (SUID), particularly when associated with external stressors such as asphyxia, which is commonly seen in many infant death scenes...
June 29, 2017: Journal of Clinical Pathology
https://www.readbyqxmd.com/read/28648120/long-qt-syndrome-associated-caveolin-3-mutations-differentially-regulate-the-hyperpolarization-activated-cyclic-nucleotide-gated-channel-4
#7
L J Motloch, R Larbig, T Darabi, S Reda, K A Motloch, B Wernly, M Lichtenauer, T Gebing, A Schwaiger, N Zagidullin, M Wolny, U C Hoppe
Background Caveolin-3 (cav-3) mutations are linked to the long-QT syndrome (LQTS) causing distinct clinical symptoms. Hyperpolarization-activated cyclic nucleotide channel 4 (HCN4) underlies the pacemaker current If. It associates with cav-3 and both form a macromolecular complex. Methods To examine the effects of human LQTS-associated cav-3 mutations on HCN4-channel function, HEK293-cells were cotransfected with HCN4 and wild-type (WT) cav-3 or a LQTS-associated cav-3 mutant (T78M, A85T, S141R, or F97C). HCN4 currents were recorded using the whole-cell patch-clamp technique...
June 26, 2017: Physiology International
https://www.readbyqxmd.com/read/28619993/low-extracellular-potassium-prolongs-repolarization-and-evokes-early-afterdepolarization-in-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#8
Jukka Kuusela, Kim Larsson, Disheet Shah, Chandra Prajapati, Katriina Aalto-Setälä
Long QT syndrome (LQTS) is characterized by a prolonged QT-interval on electrocardiogram and by increased risk of sudden death. One of the most common and potentially life-threatening electrolyte disturbances is hypokalemia, characterized by low concentrations of K(+) Using a multielectrode array platform and current clamp technique, we investigated the effect of low extracellular K(+) concentration ([K(+)]Ex) on the electrophysiological properties of hiPSC-derived cardiomyocytes (CMs) generated from a healthy control subject (WT) and from two symptomatic patients with type 1 of LQTS carrying G589D (LQT1A) or IVS7-2A>G mutation (LQT1B) in KCNQ1 The baseline prolongations of field potential durations (FPDs) and action potential durations (APDs) were longer in LQT1-CMs than in WT-CMs...
June 15, 2017: Biology Open
https://www.readbyqxmd.com/read/28607621/epicardially-placed-implantable-cardioverter-defibrillator-for-a-child-with-congenital-long-qt-syndrome
#9
Hirotaro Sugiyama, Motomi Tachibana, Hiroshi Morita, Nobuhiro Nishii, Akihito Miyoshi, Hiroyasu Sugiyama, Koji Nakagawa, Atsuyuki Watanabe, Kazufumi Nakamura, Hiroshi Ito
A 7-year-old boy presented at our hospital with syncope. At birth, electrocardiography had shown a long QT interval with torsade de pointes (TdP). Congenital long QT syndrome (LQTS) had been diagnosed by genetic testing, and was successfully controlled with oral propranolol. At age 7, TdP had recurred with syncope. Electrocardiography revealed a prominent long QT interval with T-wave alternans. The propranolol dose was increased, but TdP remained uncontrolled. A cardioverter-defibrillator (ICD) was implanted epicardially, and TdP completely resolved with atrial pacing...
June 2017: Journal of Arrhythmia
https://www.readbyqxmd.com/read/28606656/divergent-antiarrhythmic-effects-of-resveratrol-and-piceatannol-in-a-whole-heart-model-of-long-qt-syndrome
#10
Christian Ellermann, Julian Wolfes, Simon Kochhäuser, Dirk G Dechering, Florian Reinke, Kristina Wasmer, Lars Eckardt, Gerrit Frommeyer
BACKGROUND: The polyphenol resveratrol and its metabolite piceatannol have beneficial health effects including antiarrhythmic properties in ischemia/reperfusion. The objective of this study was to determine potential antiarrhythmic effects in acquired long-QT-syndrome (LQTS). METHODS AND RESULTS: 26 rabbit hearts were isolated and Langendorff-perfused. The IKr-blocker sotalol (100μM) was infused to mimic LQTS-2. Hearts were assigned to two groups. Sotalol significantly prolonged action potential duration (APD90) and QT-interval in both groups (group 1:APD90: +18ms, p<0...
June 3, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28595573/a-novel-kcnq1-nonsense-variant-in-the-isoform-specific-first-exon-causes-both-jervell-and-lange-nielsen-syndrome-1-and-long-qt-syndrome-1-a-case-report
#11
Motoi Nishimura, Marehiko Ueda, Ryota Ebata, Emi Utsuno, Takuma Ishii, Kazuyuki Matsushita, Osamu Ohara, Naoki Shimojo, Yoshio Kobayashi, Fumio Nomura
BACKGROUND: According to previous KCNQ1 (potassium channel, voltage gated, KQT-like subfamily, member 1) gene screening studies, missense variants, but not nonsense or frame-shift variants, cause the majority of long QT syndrome (LQTS; Romano-Ward syndrome [RWS]) 1 cases. Several missense variants are reported to cause RWS by a dominant-negative mechanism, and some KCNQ1 variants can cause both Jervell and Lange-Nielsen Syndrome (JLNS; in an autosomal recessive manner) and LQTS1 (in an autosomal dominant manner), while other KCNQ1 variants cause only JLNS...
June 8, 2017: BMC Medical Genetics
https://www.readbyqxmd.com/read/28575668/cryo-em-structure-of-a-kcnq1-cam-complex-reveals-insights-into-congenital-long-qt-syndrome
#12
Ji Sun, Roderick MacKinnon
KCNQ1 is the pore-forming subunit of cardiac slow-delayed rectifier potassium (IKs) channels. Mutations in the kcnq1 gene are the leading cause of congenital long QT syndrome (LQTS). Here, we present the cryoelectron microscopy (cryo-EM) structure of a KCNQ1/calmodulin (CaM) complex. The conformation corresponds to an "uncoupled," PIP2-free state of KCNQ1, with activated voltage sensors and a closed pore. Unique structural features within the S4-S5 linker permit uncoupling of the voltage sensor from the pore in the absence of PIP2...
June 1, 2017: Cell
https://www.readbyqxmd.com/read/28559636/treating-an-adolescent-with-long-qt-syndrome-for-bipolar-disorder-a-case-presentation
#13
Özlem Önen, Ayşe Kutlu, Handan Özek Erkuran
OBJECTIVES: Long QT syndrome (LQTS) is described as the development of sudden syncope attacks or death as a result of ventricular tachycardia (VT) episodes that might be observed as elongated QT interval in electrocardiography (ECG). Implantable Cardioverter Defibrillator (ICD) is recommended as first-line treatment for the condition in guidelines. We aimed to present an adolescent recently diagnosed with Bipolar Disorder (BD) who had LQTS that was treated with ICD, discussing her follow up and treatment along with relevant literature...
January 26, 2017: Psychopharmacology Bulletin
https://www.readbyqxmd.com/read/28532774/genotype-positive-long-qt-syndrome-in-patients-with-coexisting-congenital-heart-disease
#14
Mohammed A Ebrahim, Matthew R Williams, Suzanne Shepard, James C Perry
Congenital long QT syndrome (LQTS) is characterized by QT prolongation with predisposition to life-threatening arrhythmia. There have been sporadic reports of LQTS coexisting with more common forms of congenital heart disease (CHD). However, the diagnosis of LQTS when CHD is present may be confounded by several common variables including postoperative electromechanical factors predisposing to ventricular arrhythmia, intrinsic, and postoperative QRS abnormalities. This report documents a single-center experience with patients who have both genetically confirmed LQTS and CHD to examine their modes of presentation and factors associated with making the diagnosis of LQTS in this patient population, as well as potential confounding variables that may mask or delay both LQTS diagnosis and initiation of therapy...
July 15, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/28521025/mechanism-of-as2o3-induced-action-potential-prolongation-and-using-hips-cms-to-evaluate-the-rescue-efficacy-of-drugs-with-different-rescue-mechanism
#15
Meng Yan, Lifang Feng, Yanhui Shi, Junnan Wang, Yan Liu, Fengmei Li, Baoxin Li
Arsenic trioxide (As2O3) has been verified as a breakthrough in the management of acute promyelocytic leukemia in recent decades. However, cardiotoxicity, especially long QT syndrome (LQTS) has become the most important issue during As2O3 treatment. The characterized mechanisms behind this adverse effect are inhibition of cardiac hERG channel trafficking and increase of cardiac calcium currents. In our study, we found a new pathway underlying As2O3-induced cardiotoxicity that As2O3 accelerates lysosomal degradation of hERG on plasma membrane after using brefeldin A (BFA) to block protein trafficking...
May 17, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28499268/first-universal-pharmacophore-model-for-herg1-k-channel-activators-acther
#16
Serdar Durdagi, Ismail Erol, Ramin Ekhteiari Salmas, Matthew Patterson, Sergei Y Noskov
The intra-cavitary drug blockade of hERG1 channel has been extensively studied, both experimentally and theoretically. Structurally diverse ligands inadvertently block the hERG1 K(+) channel currents lead to drug induced Long QT Syndrome (LQTS). Accordingly, designing either hERG1 channel openers or current activators, with the potential to target other binding pockets of the channel, has been introduced as a viable approach in modern anti-arrhythmia drug development. However, reports and investigations on the molecular mechanisms underlying activators binding to the hERG1 channel remain sparse and the overall molecular design principles are largely unknown...
April 5, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28495999/%C3%AE-arrestin-mediated-regulation-of-the-human-ether-a-go-go-related-gene-herg-potassium-channel
#17
Matthew G Sangoi, Shawn M Lamothe, Jun Guo, Tonghua Yang, Wentao Li, Ellen G Avery, John T Fisher, Shetuan Zhang
The rapidly activating delayed rectifier K(+) channel (IKr) is encoded by the human ether-a-go-go-related gene (hERG), which is important for the repolarization of the cardiac action potential. Mutations in hERG or drugs can impair the function or decrease the expression level of hERG channels, leading to long QT syndrome (LQTS). Thus, it is important to understand hERG channel trafficking and its regulation. For this purpose, G protein-coupled receptors (GPCRs), which regulate a vast array of cellular processes, represent a useful route...
May 11, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/28492533/gene-patents-still-alive-and-kicking-their-impact-on-provision-of-genetic-testing-for-long-qt-syndrome-in-the-canadian-public-health-care-system
#18
Sarah E Ali-Khan, E Richard Gold
PurposeAlthough the Supreme Court of the United States limited their availability in Association for Molecular Pathology v. Myriad Genetics, gene patents remain important around the world. We examine the situation in Canada, where gene patents continue to exist, in light of recent litigation relating to familial long QT syndrome (LQTS).MethodsWe conducted in-depth semistructured interviews with 25 stakeholders across five Canadian provinces and supplemented this with a case analysis of the litigation.ResultsThe majority of LQTS testing was carried out outside Canada...
May 11, 2017: Genetics in Medicine: Official Journal of the American College of Medical Genetics
https://www.readbyqxmd.com/read/28490617/systemic-inflammation-as-a-novel-qt-prolonging-risk-factor-in-patients-with-torsades-de-pointes
#19
Pietro Enea Lazzerini, Franco Laghi-Pasini, Iacopo Bertolozzi, Gabriella Morozzi, Sauro Lorenzini, Antonella Simpatico, Enrico Selvi, Maria Romana Bacarelli, Francesco Finizola, Francesca Vanni, Deana Lazaro, Ademuyiwa Aromolaran, Nabil El Sherif, Mohamed Boutjdir, Pier Leopoldo Capecchi
OBJECTIVE: Increasing evidence indicates systemic inflammation as a new potential cause of acquired long QT syndrome (LQTS), via cytokine-mediated changes in cardiomyocyte ion channels. Torsade de pointes (TdP) is a life-threatening polymorphic ventricular tachycardia occurring in patients with LQTS, usually when multiple QT-prolonging factors are simultaneously present. Since classical risk factors cannot fully explain TdP events in a number of patients, we hypothesised that systemic inflammation may represent a currently overlooked risk factor contributing to TdP development in the general population...
May 10, 2017: Heart: Official Journal of the British Cardiac Society
https://www.readbyqxmd.com/read/28479515/phase-contrast-magnet-resonance-imaging-reveals-regional-transmural-and-base-to-apex-dispersion-of-mechanical-dysfunction-in-patients-with-long-qt-syndrome
#20
Johannes Brado, Markus J Dechant, Marius Menza, Adriana Komancsek, Corinna N Lang, Heiko Bugger, Daniela Foell, Bernd A Jung, Brigitte Stiller, Christoph Bode, Katja E Odening
BACKGROUND: Regional dispersion of prolonged repolarization is a hallmark of long QT syndrome (LQTS). We have also revealed regional heterogeneities in mechanical dysfunction in transgenic rabbit models of LQTS. OBJECTIVE: In this clinical pilot study, we investigated whether patients with LQTS exhibit dispersion of mechanical/diastolic dysfunction. METHODS: Nine pediatric patients with genotyped LQTS (12.2 ± 3.3 years) and 9 age- and sex-matched healthy controls (10...
May 4, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
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