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Long qt syndrome

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https://www.readbyqxmd.com/read/29467678/structural-immaturity-of-human-ipsc-derived-cardiomyocytes-in-silico-investigation-of-effects-on-function-and-disease-modeling
#1
Jussi T Koivumäki, Nikolay Naumenko, Tomi Tuomainen, Jouni Takalo, Minna Oksanen, Katja A Puttonen, Šárka Lehtonen, Johanna Kuusisto, Markku Laakso, Jari Koistinaho, Pasi Tavi
Background: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have emerged as a promising experimental tool for translational heart research and drug development. However, their usability as a human adult cardiomyocyte model is limited by their functional immaturity. Our aim is to analyse quantitatively those characteristics and how they differ from adult CMs. Methods and Results: We have developed a novel in silico model with all essential functional electrophysiology and calcium handling features of hiPSC-CMs...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29461511/roles-of-a-kinase-anchoring-proteins-and-phosphodiesterases-in-the-cardiovascular-system
#2
REVIEW
Maria Ercu, Enno Klussmann
A-kinase anchoring proteins (AKAPs) and cyclic nucleotide phosphodiesterases (PDEs) are essential enzymes in the cyclic adenosine 3'-5' monophosphate (cAMP) signaling cascade. They establish local cAMP pools by controlling the intensity, duration and compartmentalization of cyclic nucleotide-dependent signaling. Various members of the AKAP and PDE families are expressed in the cardiovascular system and direct important processes maintaining homeostatic functioning of the heart and vasculature, e.g., the endothelial barrier function and excitation-contraction coupling...
February 20, 2018: Journal of Cardiovascular Development and Disease
https://www.readbyqxmd.com/read/29457121/anesthesia-for-patients-with-ptrf-mutations-a-case-report
#3
Atsuko Hirano, Tomohiko Takada, Mariko Senda, Hidemasa Takahashi, Takeo Suzuki
Background: Polymeraze I and transcript release factor ( PTRF ) mutations are a newly recognized disease, which cause congenital generalized lipodystrophy associated with myopathy. Case presentation: A 29-year-old man (height 126 cm; weight 22 kg) with a PTRF mutation was scheduled for mandibular dentigerous cystectomy. His primary symptoms were lipodystrophy, myopathy, long QT syndrome, refractory nephrosis, and abnormal lipid metabolism. Defibrillator pads were applied soon after the patient entered the operating room...
2018: JA Clin Rep
https://www.readbyqxmd.com/read/29449639/a-herg-mutation-e1039x-produced-a-synergistic-lesion-on-i-ks-together-with-kcnq1-r174c-mutation-in-a-lqts-family-with-three-compound-mutations
#4
Jie Wu, Yuka Mizusawa, Seiko Ohno, Wei-Guang Ding, Takashi Higaki, Qi Wang, Hirohiko Kohjitani, Takeru Makiyama, Hideki Itoh, Futoshi Toyoda, Andrew F James, Jules C Hancox, Hiroshi Matsuura, Minoru Horie
Congenital long QT syndrome (LQTS) caused by compound mutations is usually associated with more severe clinical phenotypes. We identified a LQTS family harboring three compound mutations in different genes (KCNQ1-R174C, hERG-E1039X and SCN5A-E428K). KCNQ1-R174C, hERG-E1039X and SCN5A-E428K mutations and/or relevant wild-type (WT) cDNAs were respectively expressed in mammalian cells. I Ks -like, I Kr -like, I Na -like currents and the functional interaction between KCNQ1-R174C and hERG-E1039X channels were studied using patch-clamp and immunocytochemistry techniques...
February 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29445055/an-inappropriate-shock-case-early-after-implantation-of-a-subcutaneous-cardiac-defibrillator-by-subcutaneous-entrapped-air
#5
Yuka Taguchi, Toshiyuki Ishikawa, Katsumi Matsumoto, Yutaka Ogino, Hirooki Matsushita, Kohei Iguchi, Junya Hosoda
A 17-year-old woman was resuscitated from cardiac arrest due to ventricular fibrillation and was diagnosed with concealed long QT syndrome. She underwent subcutaneous implantable cardiac defibrillator (S-ICD) implantation at our hospital. The device electrogram immediately after implantation was normal. Four days after implantation, she received an inappropriate shock. The device interrogation revealed a continuous baseline shift and frequent oversensing for low amplitude signals, followed by a shock. A chest radiograph in the orthogonal view showed entrapped subcutaneous air surrounding the distal electrode...
February 14, 2018: International Heart Journal
https://www.readbyqxmd.com/read/29444113/effects-of-protein-protein-interactions-and-ligand-binding-on-the-ion-permeation-in-kcnq1-potassium-channel
#6
Horia Jalily Hasani, Aravindhan Ganesan, Marawan Ahmed, Khaled H Barakat
The voltage-gated KCNQ1 potassium ion channel interacts with the type I transmembrane protein minK (KCNE1) to generate the slow delayed rectifier (IKs) current in the heart. Mutations in these transmembrane proteins have been linked with several heart-related issues, including long QT syndromes (LQTS), congenital atrial fibrillation, and short QT syndrome. Off-target interactions of several drugs with that of KCNQ1/KCNE1 ion channel complex have been known to cause fatal cardiac irregularities. Thus, KCNQ1/KCNE1 remains an important avenue for drug-design and discovery research...
2018: PloS One
https://www.readbyqxmd.com/read/29441683/cardiovascular-safety-of-prokinetic-agents-a-focus-on-drug-induced-arrhythmias
#7
REVIEW
J R Giudicessi, M J Ackerman, M Camilleri
BACKGROUND: Gastrointestinal sensorimotor dysfunction underlies a wide range of esophageal, gastric, and intestinal motility and functional disorders that collectively constitute nearly half of all referrals to gastroenterologists. As a result, substantial effort has been dedicated toward the development of prokinetic agents intended to augment or restore normal gastrointestinal motility. However, the use of several clinically efficacious gastroprokinetic agents, such as cisapride, domperidone, erythromycin, and tegaserod, is associated with unfavorable cardiovascular safety profiles, leading to restrictions in their use...
February 14, 2018: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/29439887/a-challenge-for-mutation-specific-risk-stratification-in-long-qt-syndrome-type-1
#8
Noriaki Yagi, Hideki Itoh, Takashi Hisamatsu, Yukinori Tomita, Hiromi Kimura, Yusuke Fujii, Takeru Makiyama, Minoru Horie, Seiko Ohno
BACKGROUND: The relationship between mutation locations in KCNQ1 which is a major gene in long QT syndrome (LQTS) and phenotype has been analyzed and used for risk stratification. Mutations in the transmembrane region (TM) or cytoplasmic-loop (C-loop) are associated with more frequent cardiac events than those in other regions. However, accumulation of LQTS type 1 (LQT1) patients poses the question of whether the location specific risk stratification is really effective. METHODS: The study cohort consisted of 67 KCNQ1 mutation carriers and 13 family members who were suspected as having LQTS due to sudden cardiac death or syncope from 36 unrelated families...
February 10, 2018: Journal of Cardiology
https://www.readbyqxmd.com/read/29434162/bradycardia-is-a-specific-phenotype-of-catecholaminergic-polymorphic-ventricular-tachycardia-induced-by-ryr2-mutations
#9
Kazuaki Miyata, Seiko Ohno, Hideki Itoh, Minoru Horie
Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a lethal inherited disease characterized by ventricular arrhythmias induced by physical exercise or emotional stress. The major cause of CPVT is mutations in RYR2, which encodes the cardiac ryanodine receptor channel. Recent advances in sequencing technology have yielded incidental findings of RYR2 variants in other cardiac diseases. Analyzing the characteristics of RYR2 variants related to CPVT will be useful for differentiation from those related to other cardiac diseases...
February 9, 2018: Internal Medicine
https://www.readbyqxmd.com/read/29431731/physiological-genomics-identifies-genetic-modifiers-of-long-qt-syndrome-type-2-severity
#10
Sam Chai, Xiaoping Wan, Angelina Ramirez-Navarro, Paul J Tesar, Elizabeth S Kaufman, Eckhard Ficker, Alfred L George, Isabelle Deschênes
Congenital long QT syndrome (LQTS) is an inherited channelopathy associated with life-threatening arrhythmias. LQTS type 2 (LQT2) is caused by mutations in KCNH2, which encodes the potassium channel hERG. We hypothesized that modifier genes are partly responsible for the variable phenotype severity observed in some LQT2 families. Here, we identified contributors to variable expressivity in an LQT2 family by using induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) and whole exome sequencing in a synergistic manner...
February 12, 2018: Journal of Clinical Investigation
https://www.readbyqxmd.com/read/29431662/classification-and-reporting-of-potentially-proarrhythmic-common-genetic-variation-in-long-qt-syndrome-genetic-testing
#11
REVIEW
John R Giudicessi, Dan M Roden, Arthur A M Wilde, Michael J Ackerman
The acquired and congenital forms of long QT syndrome represent 2 distinct but clinically and genetically intertwined disorders of cardiac repolarization characterized by the shared final common pathway of QT interval prolongation and risk of potentially life-threatening arrhythmias. Over the past 2 decades, our understanding of the spectrum of genetic variation that (1) perturbs the function of cardiac ion channel macromolecular complexes and intracellular calcium-handling proteins, (2) underlies acquired/congenital long QT syndrome susceptibility, and (3) serves as a determinant of QT interval duration in the general population has grown exponentially...
February 6, 2018: Circulation
https://www.readbyqxmd.com/read/29427819/significance-of-t-wave-inversion-triggered-by-spontaneous-atrial-premature-beats-in-patients-with-long-qt-syndrome
#12
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 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 a high risk of Torsade de Pointes (TdP) may exhibit momentary atrial or sinoatrial premature beat-induced T-wave inversion (APB-TWI). OBJECTIVE: To assess the association of APB-TWI with TdP history and with microvolt TWA. METHODS: 24-h 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/29423467/an-automated-microfluidic-dna-microarray-platform-for-genetic-variant-detection-in-inherited-arrhythmic-diseases
#13
Shu-Hong Huang, Yu-Shin Chang, Jyh-Ming Jimmy Juang, Kai-Wei Chang, Mong-Hsun Tsai, Tzu-Pin Lu, Liang-Chuan Lai, Eric Y Chuang, Nien-Tsu Huang
In this study, we developed an automated microfluidic DNA microarray (AMDM) platform for point mutation detection of genetic variants in inherited arrhythmic diseases. The platform allows for automated and programmable reagent sequencing under precise conditions of hybridization flow and temperature control. It is composed of a commercial microfluidic control system, a microfluidic microarray device, and a temperature control unit. The automated and rapid hybridization process can be performed in the AMDM platform using Cy3 labeled oligonucleotide exons of SCN5A genetic DNA, which produces proteins associated with sodium channels abundant in the heart (cardiac) muscle cells...
February 9, 2018: Analyst
https://www.readbyqxmd.com/read/29415258/a-long-term-open-label-study-to-evaluate-the-safety-and-tolerability-of-brexpiprazole-as-maintenance-treatment-in-adults-with-schizophrenia
#14
Andy Forbes, Mary Hobart, John Ouyang, Lily Shi, Stephanie Pfister, Mika Hakala
Background: Brexpiprazole is a serotonin-dopamine activity modulator with efficacy in acute schizophrenia and relapse prevention. The aim of this Phase 3, multicenter study was to assess the long-term safety, tolerability, and efficacy of treatment with brexpiprazole flexible-dose 1-4 mg/day. Methods: Patients rolled over into this 52-week open-label study (amended to 26 weeks towards the end) from three randomized, double-blind, placebo-controlled Phase 3 studies...
February 3, 2018: International Journal of Neuropsychopharmacology
https://www.readbyqxmd.com/read/29414256/updated-recommendations-for-athletes-with-heart-disease
#15
Rachel Lampert, Douglas P Zipes
Professional society recommendations to decrease sudden cardiac death in athletes, including eligibility requirements with disqualification for athletes with diagnosed disease as well as preparticipation screening and emergency preparedness, were updated in 2015. The update includes new sections on aortic disease, channelopathies, and sickle cell trait, as well as a change in format from the previous binary yes/no format to the more nuanced and contemporary "class and level of evidence" format. Eighty-four of the 246 recommendations now carry Class II designation-"reasonable," or "may be considered...
January 29, 2018: Annual Review of Medicine
https://www.readbyqxmd.com/read/29413968/current-perspective-osimertinib-induced-qt-prolongation-new-drugs-with-new-side-effects-need-careful-patient-monitoring
#16
Mart Schiefer, Lizza E L Hendriks, Trang Dinh, Ulrich Lalji, Anne-Marie C Dingemans
An increasing number of tyrosine kinase inhibitors (TKIs) are available for the treatment of non-small cell lung cancer (NSCLC). QT prolongation is one of the known, but relatively rare, adverse events of several TKIs (e.g. osimertinib, crizotinib, ceritinib). Screening for QT prolongation in (high risk) patients is advised for these TKIs. When a QT prolongation develops, the physician is challenged with the question whether to (permanently) discontinue the TKI. In this perspective, we report on a patient who developed a grade III QT prolongation during osimertinib (a third-generation epidermal growth factor receptor [EGFR]-TKI) treatment...
March 2018: European Journal of Cancer
https://www.readbyqxmd.com/read/29408217/autonomic-conflict-exacerbates-long-qt-associated-ventricular-arrhythmia
#17
James Winter, Michael Tipton, Michael J Shattock
This study tested the hypothesis that concomitant sympathetic and parasympathetic stimulation ("autonomic conflict") may act as a trigger for arrhythmia in long QT syndrome (LQTS). Studies were performed in isolated innervated rabbit hearts treated with clofilium (100 nmol/L); a potassium channel blocker. The influence of vagus nerve stimulation (VNS) on spontaneous ventricular arrhythmia was assessed in the absence/presence of sustained noradrenaline perfusion (100 nmol/L) and with sudden adrenergic stress (injections of noradrenaline into the perfusion line)...
February 2, 2018: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/29407091/estradiol-protection-against-toxic-effects-of-catecholamine-on-electrical-properties-in-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#18
Ibrahim El-Battrawy, Zhihan Zhao, Huan Lan, Jan-Dierk Schünemann, Katherine Sattler, Fanis Buljubasic, Bence Patocskai, Xin Li, Gökhan Yücel, Siegfried Lang, Daniel Nowak, Lukas Cyganek, Karen Bieback, Jochen Utikal, Wolfram-Hubertus Zimmermann, Ursula Ravens, Thomas Wieland, Martin Borggrefe, Xiao-Bo Zhou, Ibrahim Akin
BACKGROUND AND PURPOSE: Previous studies revealed that Takotsubo cardiomyopathy (TTC), a transient disorder of ventricular dysfunction affecting predominantly postmenopausal women, is associated with acquired long QT syndrome and arrhythmias, but the exact pathophysiologic mechanism is unknown. Our aim is to investigate the electrophysiological mechanism for QT-prolongation in TTC-patients by using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). METHODS: hiPSC-CMs, which were generated from human skin fibroblasts of three healthy donors, were treated by estradiol (10μM for one week) and a toxic concentration of isoprenaline (Iso, 1mM for 2h)...
March 1, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29405316/acquired-long-qt-syndrome-and-torsade-de-pointes
#19
REVIEW
Nabil El-Sherif, Gioia Turitto, Mohamed Boutjdir
Since its initial description by Jervell and Lange-Nielsen in 19571 , the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS continues to remain the domain of cardiologists, cardiac electrophysiologists, and specialized centers, the by far more frequent acquired drug-induced LQTS is the domain of all physicians and other members of the health care team who are required to make therapeutic decisions. This report will review the electrophysiological mechanisms of LQTS and TdP, electrocardiographic (ECG) characteristics of acquired LQTS, its clinical presentation, management, and future directions in the field...
February 6, 2018: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/29402340/whole-exome-sequencing-identifies-a-novel-scn5a-mutation-c335r-in-a-chinese-family-with-arrhythmia
#20
Hao Huang, Dong-Bo Ding, Liang-Liang Fan, Jie-Yuan Jin, Jing-Jing Li, Shuai Guo, Ya-Qin Chen, Rong Xiang
BACKGROUND: SCN5A encodes sodium-channel α-subunit Nav1.5. The mutations of SCN5A can lead to hereditary cardiac arrhythmias such as the long-QT syndrome type 3 and Brugada syndrome. Here we sought to identify novel mutations in a family with arrhythmia. METHODS: Genomic DNA was isolated from blood of the proband, who was diagnosed with atrial flutter. Illumina Hiseq 2000 whole-exome sequencing was performed and an arrhythmia-related gene-filtering strategy was used to analyse the pathogenic genes...
February 6, 2018: Cardiology in the Young
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