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https://www.readbyqxmd.com/read/27690427/discovery-of-dihydrobenzoxazepinone-gs-6615-late-sodium-current-inhibitor-late-inai-a-phase-ii-agent-with-demonstrated-preclinical-anti-ischemic-and-antiarrhythmic-properties
#1
Jeff A Zablocki, Elfatih Elzein, Xiaofen Li, Dmitry O Koltun, Eric Q Parkhill, Tetsuya Kobayashi, Ruben Martinez, Britton Corkey, Haibo Jiang, Thao Perry, Rao Kalla, Gregory T Notte, Oliver Saunders, Michael Graupe, Yafan Lu, Chandru Venkataramani, Juan Guerrero, Jason Perry, Mark Osier, Robert Strickley, Gongxin Liu, Wei-Qun Wang, Lufei Hu, Xiao-Jun Li, Nesrine El-Bizri, Ryoko Hirakawa, Kris Kahlig, Cheng Xie, Cindy Hong Li, Arvinder K Dhalla, Sridharan Rajamani, Nevena Mollova, Daniel Soohoo, Eve-Irene Lepist, Bernard Murray, Gerry Rhodes, Luiz Belardinelli, Manoj C Desai
Late sodium current (late INa) is enhanced during ischemia by reactive oxygen species (ROS) modifying the Nav 1.5 channel, resulting in incomplete inactivation. Compound 4 (GS-6615, eleclazine) a novel, potent, and selective inhibitor of late INa, is currently in clinical development for treatment of long QT-3 syndrome (LQT-3), hypertrophic cardiomyopathy (HCM), and ventricular tachycardia-ventricular fibrillation (VT-VF). We will describe structure-activity relationship (SAR) leading to the discovery of 4 that is vastly improved from the first generation late INa inhibitor 1 (ranolazine)...
October 3, 2016: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/27646833/the-effects-of-pharmacological-compounds-on-beat-rate-variations-in-human-long-qt-syndrome-cardiomyocytes
#2
Jukka Kuusela, Jiyeong Kim, Esa Räsänen, Katriina Aalto-Setälä
Healthy human heart rate fluctuates overtime showing long-range fractal correlations. In contrast, various cardiac diseases and normal aging show the breakdown of fractal complexity. Recently, it was shown that human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) intrinsically exhibit fractal behavior as in humans. Here, we investigated the fractal complexity of hiPSC-derived long QT-cardiomyocytes (LQT-CMs). We recorded extracellular field potentials from hiPSC-CMs at baseline and under the effect of various compounds including β-blocker bisoprolol, ML277, a specific and potent IKs current activator, as well as JNJ303, a specific IKs blocker...
December 2016: Stem Cell Reviews
https://www.readbyqxmd.com/read/27586292/current-voltage-relationship-for-late-na-current-in-adult-rat-ventricular-myocytes
#3
R B Clark, W R Giles
It is now well established that the slowly inactivating component of the Na(+) current (INa-L) in the mammalian heart is a significant regulator of the action potential waveform. This insight has led to detailed studies of the role of INa-L in a number of important and challenging pathophysiological settings. These include genetically based ventricular arrhythmias (LQT 1, 2, and 3), ventricular arrhythmias arising from progressive cardiomyopathies (including diabetic), and proarrhythmic abnormalities that develop during local or global ventricular ischemia...
2016: Current Topics in Membranes
https://www.readbyqxmd.com/read/27401738/prominent-qtc-prolongation-in-a-patient-with-a-rare-variant-in-the-cardiac-ryanodine-receptor-gene
#4
Yuki Taniguchi, Aya Miyazaki, Heima Sakaguchi, Yousuke Hayama, Norihiro Ebishima, Jun Negishi, Kanae Noritake, Yoshihiro Miyamoto, Wataru Shimizu, Takeshi Aiba, Hideo Ohuchi
We report the case of a 12-year-old female patient with a history of four syncopal episodes related to exercise over 2 years and who showed prominent QTc prolongation on electrocardiogram; therefore, she was clinically diagnosed with long QT syndrome type-1. However, genetic analysis did not identify any LQT-related genes but showed a rare missense variant in the cardiac ryanodine receptor gene. From the results of drug-loading tests, administration of oral propranolol was initiated; thereafter, she experienced no syncopal episodes...
July 11, 2016: Heart and Vessels
https://www.readbyqxmd.com/read/27394160/experience-with-bisoprolol-in-long-qt1-and-long-qt2-syndrome
#5
Christian Steinberg, Gareth J Padfield, Basil Al-Sabeq, Arnon Adler, John A Yeung-Lai-Wah, Charles R Kerr, Marc W Deyell, Jason G Andrade, Matthew T Bennett, Raymond Yee, George J Klein, Martin Green, Zachary W M Laksman, Andrew D Krahn, Santabhanu Chakrabarti
BACKGROUND: The protective effect of beta-blockers in patients with inherited Long-QT syndrome is well established. Recent reports have suggested that beta-blockers are not equally effective in Long-QT (LQT). Bisoprolol is an attractive candidate for use in LQT because of its cardioselective properties and favorable side-effect profile. METHODS: We performed a retrospective cohort study of 114 consecutive patients with gene-positive Long-QT syndrome type 1 (LQT1) or Long-QT syndrome type 2 (LQT2) treated with bisoprolol, nadolol or atenolol with a total of 580 person-years of follow-up...
July 9, 2016: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/27054604/the-influence-of-pregnancy-in-patients-with-congenital-long-qt-syndrome
#6
Lohit Garg, Jalaj Garg, Parasuram Krishnamoorthy, Amy Ahnert, Neeraj Shah, Raman S Dusaj, Babak Bozorgnia
Congenital long QT syndrome (LQTS) is a disorder of myocardial repolarization and is characterized by a prolonged QT interval on AN electrocardiogram. A prolonged QT predisposes patients to an increased risk of syncope and sudden cardiac death secondary to polymorphic ventricular tachycardia. Several mutations linked to the LQT syndrome have been identified, the most common of which have been found in the potassium channel KCNQ1 (LQT1) and hERG (LQT2) genes and in the sodium channel SCN5A (LQT3) gene. Female gender is an independent risk factor for the development of torsades de pointes (TdP) in LQTS...
March 31, 2016: Cardiology in Review
https://www.readbyqxmd.com/read/26632536/pronounced-shortening-of-qt-interval-with-mexiletine-infusion-test-in-patients-with-type-3-congenital-long-qt-syndrome
#7
Moritoshi Funasako, Takeshi Aiba, Kohei Ishibashi, Ikutaro Nakajima, Koji Miyamoto, Yuko Inoue, Hideo Okamura, Takashi Noda, Shiro Kamakura, Toshihisa Anzai, Teruo Noguchi, Satoshi Yasuda, Yoshihiro Miyamoto, Kengo Fukushima Kusano, Hisao Ogawa, Wataru Shimizu
BACKGROUND: Mexiletine is often used for medical therapy in LQT3 patients, however, the usefulness of mexiletine infusion test for LQT3 patients has not been reported. The aim of this study was to evaluate the usefulness of mexiletine infusion test for detecting LQT3 patients. METHODS AND RESULTS: We analyzed response in 12-lead electrocardiogram parameters measured in II or V5 to i.v. mexiletine infusion (2 mg/kg) during sinus rhythm among 31 genotype-positive LQT patients (29 ± 18 years, 12 male)...
2016: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/26548443/two-cases-of-lqt-syndrome-with-malignant-syncope-after-switch-from-propranolol-to-bisoprolol
#8
Milos Kesek, Annika Rydberg, Steen M Jensen
Propranolol in slow-release form has been the first-line treatment in long QT (LQT) until it was withdrawn from the market. We describe two cases where a switch to bisoprolol resulted in worsening of arrhythmia control: A man with LQT2, asymptomatic on propranolol, experienced syncope after switching to bisoprolol 5 mg daily. He switched back to propranolol and has remained asymptomatic during subsequent 12 months. A man with classical Jervell Lange-Nielsen syndrome, previous gangliectomy, and ICD implantation, switched to bisoprolol 5 mg daily...
March 2016: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/26545904/bag3-related-myopathy-polyneuropathy-and-cardiomyopathy-with-long-qt-syndrome
#9
Anna Kostera-Pruszczyk, Małgorzata Suszek, Rafał Płoski, Maria Franaszczyk, Anna Potulska-Chromik, Piotr Pruszczyk, Elżbieta Sadurska, Justyna Karolczak, Anna M Kamińska, Maria Jolanta Rędowicz
BAG3 belongs to BAG family of molecular chaperone regulators interacting with HSP70 and anti-apoptotic protein Bcl-2. It is ubiquitously expressed with strong expression in skeletal and cardiac muscle, and is involved in a panoply of cellular processes. Mutations in BAG3 and aberrations in its expression cause fulminant myopathies, presenting with progressive limb and axial muscle weakness, and respiratory insufficiency and neuropathy. Herein, we report a sporadic case of a 15-years old girl with symptoms of myopathy, demyelinating polyneuropathy and asymptomatic long QT syndrome...
December 2015: Journal of Muscle Research and Cell Motility
https://www.readbyqxmd.com/read/26301350/a-rare-association-with-suffered-cardiac-arrest-long-qt-interval-and-syndactyly-timothy-syndrome-lqt-8
#10
Yakup Ergül, İsa Özyılmaz, Sertaç Haydın, Alper Güzeltaş, Volkan Tuzcu
No abstract text is available yet for this article.
August 2015: Anatolian Journal of Cardiology
https://www.readbyqxmd.com/read/26271031/estradiol-regulates-human-qt-interval-acceleration-of-cardiac-repolarization-by-enhanced-kcnh2-membrane-trafficking
#11
Lars Anneken, Stefan Baumann, Patrick Vigneault, Peter Biliczki, Corinna Friedrich, Ling Xiao, Zenawit Girmatsion, Ina Takac, Ralf P Brandes, Stefan Kissler, Inka Wiegratz, Sven Zumhagen, Birgit Stallmeyer, Stefan H Hohnloser, Thomas Klingenheben, Eric Schulze-Bahr, Stanley Nattel, Joachim R Ehrlich
BACKGROUND: Modulation of cardiac repolarization by sexual hormones is controversial and hormonal effects on ion channels remain largely unknown. In the present translational study, we therefore assessed the relationship between QTc duration and gonadal hormones and studied underlying mechanisms. METHODS AND RESULTS: We measured hormone levels and QTc intervals in women during clomiphene stimulation for infertility and women before, during, and after pregnancy. Three heterozygous LQT-2 patients (KCNH2-p...
February 14, 2016: European Heart Journal
https://www.readbyqxmd.com/read/26118557/obstructive-sleep-apnea-in-patients-with-congenital-long-qt-syndrome-implications-for-increased-risk-of-sudden-cardiac-death
#12
Abu S Shamsuzzaman, Virend K Somers, Timothy K Knilans, Michael J Ackerman, Yu Wang, Raouf S Amin
BACKGROUND: Congenital long QT syndrome (LQTS) is a familial arrhythmogenic cardiac channelopathy characterized by prolonged ventricular repolarization and increased risk of torsades de pointes-mediated syncope, seizures, and sudden cardiac death (SCD). QT prolongation corrected for heart rate (QTc) is an important diagnostic and prognostic feature in LQTS. Obstructive sleep apnea (OSA) has been increasingly implicated in the pathogenesis of cardiovascular disease, including arrhythmias and SCD...
July 1, 2015: Sleep
https://www.readbyqxmd.com/read/26070071/electrocardiographic-screening-for-prolonged-qt-interval-to-reduce-sudden-cardiac-death-in-psychiatric-patients-a-cost-effectiveness-analysis
#13
Antoine Poncet, Baris Gencer, Marc Blondon, Marianne Gex-Fabry, Christophe Combescure, Dipen Shah, Peter J Schwartz, Marie Besson, François R Girardin
IMPORTANCE: Sudden cardiac death is a leading cause of mortality in psychiatric patients. Long QT (LQT) is common in this population and predisposes to Torsades-de-Pointes (TdP) and subsequent mortality. OBJECTIVE: To estimate the cost-effectiveness of electrocardiographic screening to detect LQT in psychiatric inpatients. DESIGN, SETTING, AND PARTICIPANTS: We built a decision analytic model based on a decision tree to evaluate the cost-effectiveness and utility of LQT screening from a health care perspective...
2015: PloS One
https://www.readbyqxmd.com/read/25967940/assessment-of-the-predictive-accuracy-of-five-in-silico-prediction-tools-alone-or-in-combination-and-two-metaservers-to-classify-long-qt-syndrome-gene-mutations
#14
Ivone U S Leong, Alexander Stuckey, Daniel Lai, Jonathan R Skinner, Donald R Love
BACKGROUND: Long QT syndrome (LQTS) is an autosomal dominant condition predisposing to sudden death from malignant arrhythmia. Genetic testing identifies many missense single nucleotide variants of uncertain pathogenicity. Establishing genetic pathogenicity is an essential prerequisite to family cascade screening. Many laboratories use in silico prediction tools, either alone or in combination, or metaservers, in order to predict pathogenicity; however, their accuracy in the context of LQTS is unknown...
May 13, 2015: BMC Medical Genetics
https://www.readbyqxmd.com/read/25923442/eag-domains-regulate-lqt-mutant-herg-channels-in-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#15
Qiang-Ni Liu, Matthew C Trudeau
Human Ether á go-go Related Gene potassium channels form the rapid component of the delayed-rectifier (IKr) current in the heart. The N-terminal 'eag' domain, which is composed of a Per-Arnt-Sim (PAS) domain and a short PAS-cap region, is a critical regulator of hERG channel function. In previous studies, we showed that isolated eag (i-eag) domains rescued the dysfunction of long QT type-2 associated mutant hERG R56Q channels, by substituting for defective eag domains, when the channels were expressed in Xenopus oocytes or HEK 293 cells...
2015: PloS One
https://www.readbyqxmd.com/read/25902397/maternal-and-neonatal-outcomes-in-labor-and-at-delivery-when-long-qt-syndrome-is-present
#16
Hiroaki Tanaka, Shinji Katsuragi, Kayo Tanaka, Masami Sawada, Naoko Iwanaga, Jun Yoshimatsu, Tomoaki Ikeda
OBJECTIVE: Women during labor may be susceptible to torsades de pointes (TdP), which may cause the fetal condition to deteriorate. The aim of the present investigation was to analyze maternal and fetal outcomes during labor when long QT syndrome (LQTS) was present. METHODS: We examined the maternal and neonatal outcomes of 25 pregnancies (18 women) with LQT between 1995 and 2012 at the Department of Perinatology, National Cardiovascular Center, Japan. Maternal and neonatal outcomes including cardiovascular events, cardiovascular events within a week after delivery, caesarean delivery rate, still births, preterm births, and non-reassuring fetal heart rate pattern (NRFHR) during labor were investigated...
2016: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/25825456/dual-lqt1-and-hcm-phenotypes-associated-with-tetrad-heterozygous-mutations-in-kcnq1-myh7-mylk2-and-tmem70-genes-in-a-three-generation-chinese-family
#17
Lifeng Wang, Lei Zuo, Jing Hu, Hong Shao, Changhui Lei, Wei Qi, Ying Liu, Yunbo Miao, Xuan Ma, Christopher L-H Huang, Bo Wang, Xiaodong Zhou, Yanmin Zhang, Liwen Liu
AIMS: Hypertrophic cardiomyopathy (HCM) mainly results from autosomal-dominant inherited single heterozygous mutations in cardiac sarcomere genes. Contributions of multiple gene mutations to disease heterogeneity in a three-generation family were investigated. METHODS: Clinical, electrocardiographic (ECG), and echocardiographic examination in members of a three-generation Chinese family was followed by exon and boarding intron analysis of 96 genes in the proband using second-generation sequencing...
April 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/25713300/treatment-of-cardiac-arrhythmias-in-a-mouse-model-of-rett-syndrome-with-na-channel-blocking-antiepileptic-drugs
#18
José A Herrera, Christopher S Ward, Meagan R Pitcher, Alan K Percy, Steven Skinner, Walter E Kaufmann, Daniel G Glaze, Xander H T Wehrens, Jeffrey L Neul
One quarter of deaths associated with Rett syndrome (RTT), an X-linked neurodevelopmental disorder, are sudden and unexpected. RTT is associated with prolonged QTc interval (LQT), and LQT-associated cardiac arrhythmias are a potential cause of unexpected death. The standard of care for LQT in RTT is treatment with β-adrenergic antagonists; however, recent work indicates that acute treatment of mice with RTT with a β-antagonist, propranolol, does not prevent lethal arrhythmias. In contrast, acute treatment with the Na(+) channel blocker phenytoin prevented arrhythmias...
April 2015: Disease Models & Mechanisms
https://www.readbyqxmd.com/read/25645639/further-evidence-of-the-association-between-lqt-syndrome-and-epilepsy-in-a-family-with-kcnq1-pathogenic-variant
#19
Coloma Tiron, Coloma Tiron de Llano, Oscar Campuzano, Alexandra Pérez-Serra, Irene Mademont, Monica Coll, Catarina Allegue, Anna Iglesias, Sara Partemi, Pasquale Striano, Antonio Oliva, Ramon Brugada
PURPOSE: Ion channels are expressed both in the heart and in the brain, being advocated as responsible for sudden unexpected death in epilepsy but few pathogenic mutations have been identified. We aim to identify a novel gen associated with channelopathies and epilepsy in a family. METHODS: We assessed a family showing epilepsy concomitant with LQTS. Index case showed prolonged QT interval. His father suffers of LQT and epilepsy. We performed a direct sequencing analysis of KCNQ1, KCNH2, KCNE1, KCNE2 and SCN5A genes...
February 2015: Seizure: the Journal of the British Epilepsy Association
https://www.readbyqxmd.com/read/25634837/physiological-variations-environmental-factors-and-genetic-modifications-in-inherited-lqt-syndromes
#20
EDITORIAL
Robert J Myerburg
No abstract text is available yet for this article.
February 3, 2015: Journal of the American College of Cardiology
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