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Long qt syndrome

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https://www.readbyqxmd.com/read/27921062/long-qt-syndrome-and-duodenal-ampullary-adenoma-a-new-association
#1
F N U Asad-Ur-Rahman, Laura Hughes, Muhammad Talha Khan, Muhammad Khalid Hasan, Irteza Inayat
KCNQ1 gene mutation has a well-known association with long QT syndrome (LQTS). However, recent studies suggest that it may be implicated in intestinal neoplasia. We present a 27-year-old Hispanic man with a known history of LQTS secondary to KCNQ1 mutation, who presented with painless jaundice. Endoscopic retrograde pancreatic cholangiography revealed a prominent ampulla, with histology consistent with ampullary adenoma with high-grade dysplasia. Further endoscopic studies did not suggest familial adenomatous polyposis...
August 2016: ACG Case Reports Journal
https://www.readbyqxmd.com/read/27920829/clinical-and-genetic-features-of-australian-families-with-long-qt-syndrome-a-registry-based-study
#2
Charlotte Burns, Jodie Ingles, Andrew M Davis, Vanessa Connell, Belinda Gray, Lauren Hunt, Julie McGaughran, Christopher Semsarian
BACKGROUND: Familial long QT syndrome (LQTS) is a primary arrhythmogenic disorder caused by mutations in ion channel genes. The phenotype ranges from asymptomatic individuals to sudden cardiac arrest and death. LQTS is a rare but significant health problem for which global data should exist. This study sought to provide the first clinical and genetic description of Australian families with LQTS. METHODS: We performed a cross-sectional study to evaluate clinical and genetic features of families with LQTS...
December 2016: Journal of Arrhythmia
https://www.readbyqxmd.com/read/27916661/tetrameric-assembly-of-k-channels-requires-er-located-chaperone-proteins
#3
Kai Li, Qiang Jiang, Xue Bai, Yi-Feng Yang, Mei-Yu Ruan, Shi-Qing Cai
Tetrameric assembly of channel subunits in the endoplasmic reticulum (ER) is essential for surface expression and function of K(+) channels, but the molecular mechanism underlying this process remains unclear. In this study, we found through genetic screening that ER-located J-domain-containing chaperone proteins (J-proteins) are critical for the biogenesis and physiological function of ether-a-go-go-related gene (ERG) K(+) channels in both Caenorhabditis elegans and human cells. Human J-proteins DNAJB12 and DNAJB14 promoted tetrameric assembly of ERG (and Kv4...
November 30, 2016: Molecular Cell
https://www.readbyqxmd.com/read/27915266/systematic-ajmaline-challenge-in-patients-with-long-qt-3-syndrome-caused-by-the-most-common-mutation-a-multicentre-study
#4
Stephan Hohmann, Boris Rudic, Torsten Konrad, David Duncker, Thorben König, Erol Tülümen, Thomas Rostock, Martin Borggrefe, Christian Veltmann
AIMS: Overlap syndromes of long QT 3 syndrome (LQT3) and the Brugada syndrome (BrS) have been reported. Identification of patients with an overlapping phenotype is crucial before initiation of Class I antiarrhythmic drugs for LQT3. Aim of the present study was to elucidate the yield of ajmaline challenge in unmasking the Brugada phenotype in patients with LQT3 caused by the most common mutation, SCN5A-E1784K. METHODS AND RESULTS: Consecutive families in tertiary referral centres diagnosed with LQT3 caused by SCN5A-E1784K were included in the study...
December 2, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/27903879/the-analysis-of-qt-interval-and-repolarization-morphology-of-the-heart-in-chronic-exposure-to-lead
#5
J Kiełtucki, M Dobrakowski, N Pawlas, B Średniawa, M Boroń, S Kasperczyk
There are no common recommendations regarding electrocardiographic monitoring in occupationally exposed workers. Therefore, the present study was designed to investigate whether exposure to lead results in an increase of selected electrocardiography (ECG) pathologies, such as QT interval prolongation and repolarization disorders, in occupationally exposed workers. The study group included 180 workers occupationally exposed to lead compounds. The exposed group was divided according to the median of the mean blood lead level (PbBmean) calculated based on a series of measurements performed during 5-year observation period (35 µg/dl) into two subgroups: low exposure (LE, PbBmean = 20...
November 30, 2016: Human & Experimental Toxicology
https://www.readbyqxmd.com/read/27882731/reproducibility-of-corrected-qt-interval-in-pediatric-genotyped-long-qt-syndrome
#6
Yoshiharu Ogawa, Toshikatsu Tanaka, Sachiko Kido
Reproducibility of corrected QT interval (QTc), especially QTc after exercise, has not been thoroughly investigated. We reviewed charts of pediatric patients who underwent treadmill-exercise stress testing without medication multiple times within 1 year. In patients with long-QT syndrome (LQTS; n = 22), the discrepancy in QTc between two treadmill exercise stress tests using Fridericia's formula was 14 ± 12 ms at rest, 13 ± 12 ms 4 min after exercise, with a maximum of 14 ± 12 ms after exercise. There was no statistically significant difference in QTc between the two tests...
November 2016: Pediatrics International: Official Journal of the Japan Pediatric Society
https://www.readbyqxmd.com/read/27871843/considerations-when-using-next-generation-sequencing-for-genetic-diagnosis-of-long-qt-syndrome-in-the-clinical-testing-laboratory
#7
Hyojin Chae, Jiyeon Kim, Gun Dong Lee, Woori Jang, Joonhong Park, Dong Wook Jekarl, Yong Seog Oh, Myungshin Kim, Yonggoo Kim
BACKGROUND: Congenital long-QT syndrome (LQTS) is a potentially lethal cardiac electrophysiologic disorder characterized by QT interval prolongation and T-wave abnormalities. At least 13 LQTS-associated genes have been reported, but the high cost and low throughput of conventional Sanger sequencing has hampered the multi-gene-based LQTS diagnosis in clinical laboratories. METHODS: We developed an NGS (next-generation sequencing)-based targeted gene panel for 13 LQTS genes using the Ion PGM platform, and a cohort of 36 LQTS patients were studied for characterization of analytical performance specifications...
November 18, 2016: Clinica Chimica Acta; International Journal of Clinical Chemistry
https://www.readbyqxmd.com/read/27868350/an-elderly-jervell-and-lange-nielsen-patient-heterozygous-compound-for-two-new-kcnq1-mutations
#8
Eliecer Coto, Francisco J García-Fernández, David Calvo, Ricardo Salgado-Aranda, Javier Martín-González, Belén Alonso, Sara Iglesias, Juan Gómez
We present the case of a 66-year-old female with early onset deafness and seizures, who was diagnosed with epilepsy at the age of 2 years. She received antiepileptic drugs and was free of syncope episodes for 32 years. After a syncope at the age of 34, the ECG was characteristic of long-QT syndrome and was treated with antiarrhythmic drugs. Sequencing of the KCNQ1 gene identified two novel KCNQ1 variants interpreted to be pathogenic, and the patient was finally diagnosed with Jervell and Lange-Nielsen syndrome...
November 21, 2016: American Journal of Medical Genetics. Part A
https://www.readbyqxmd.com/read/27868338/incomplete-timothy-syndrome-secondary-to-a-mosaic-mutation-of-the-cacna1c-gene-diagnosed-using-next-generation-sequencing
#9
Amandine Baurand, Sylvie Falcon-Eicher, Gabriel Laurent, Elisabeth Villain, Caroline Bonnet, Christel Thauvin-Robinet, Caroline Jacquot, Jean-Christophe Eicher, Jean-Baptiste Gourraud, Sébastien Schmitt, Stéphane Bézieau, Mathilde Giraud, Solenne Dumont, Paul Kuentz, Vincent Probst, Antoine Burguet, Florence Kyndt, Laurence Faivre
Autosomal dominant genetic diseases can occur de novo and in the form of somatic mosaicism, which can give rise to a less severe phenotype, and make diagnosis more difficult given the sensitivity limits of the methods used. We report the case of female child with a history of surgery for syndactyly of the hands and feet, who was admitted at 6 years of age to a pediatric intensive care unit following cardiac arrest. The electrocardiogram (ECG) showed a long QT interval that on occasions reached 500 ms. Despite the absence of facial dysmorphism and the presence of normal psychomotor development, a diagnosis of Timothy syndrome was made given the association of syndactyly and the ECG features...
November 21, 2016: American Journal of Medical Genetics. Part A
https://www.readbyqxmd.com/read/27857240/detection-of-sudden-death-syndromes-in-new-zealand
#10
Nikki Earle, Jackie Crawford, Kate Gibson, Donald Love, Ian Hayes, Katherine Neas, Martin Stiles, Mandy Graham, Tom Donoghue, Andrew Aitken, Jon Skinner
AIM: To investigate regional variations in the detection of sudden death syndromes across New Zealand by assessing registrations in the national Cardiac Inherited Diseases Registry New Zealand (CIDRNZ). METHODS: The CIDRNZ has been a national entity since 2009, with a hub in Auckland and locally funded regional coordinators (Midland, Central) linked with multidisciplinary cardiac genetic teams. Registration is consent-based and voluntary, and involves the collection of clinical/genetic information and permits genetic testing and research...
November 18, 2016: New Zealand Medical Journal
https://www.readbyqxmd.com/read/27844191/-indications-for-implantable-loop-recorders-in-patients-with-channelopathies-and-ventricular-tachycardias
#11
Julia Köbe, Kristina Wasmer, Florian Reinke, Lars Eckardt
Implantable loop recorders (ILR) do not play a pivotal role in the current guidelines on ventricular arrhythmias except in identifying rhythm-symptom correlations if ventricular arrhythmias are assumed. Before a decision for a pure diagnostic implantable device is made, a thorough arrhythmic risk assessment is of major importance due to the potential lethal outcome of ventricular arrhythmias. Nevertheless, some clinical circumstances exist where long-term monitoring by an ILR may add significant information in electrical heart diseases, in patients with ventricular arrhythmias, or structural heart diseases and a potential risk of ventricular arrhythmias...
November 14, 2016: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/27836893/dynamical-mechanisms-of-phase-2-early-afterdepolarizations-in-human-ventricular-myocytes-insights-from-bifurcation-analyses-of-two-mathematical-models
#12
Yasutaka Kurata, Kunichika Tsumoto, Kenshi Hayashi, Ichiro Hisatome, Mamoru Tanida, Yuhichi Kuda, Toshishige Shibamoto
Early afterdepolarization (EAD) is known as a cause of ventricular arrhythmias in long QT syndromes. We theoretically investigated how the rapid (IKr) and slow (IKs) components of delayed-rectifier K(+) channel currents, L-type Ca(2+) channel current (ICaL), Na(+)/Ca(2+) exchanger current (INCX), Na(+)-K(+) pump current (INaK), intracellular Ca(2+) (Cai) handling via sarcoplasmic reticulum (SR) and intracellular Na(+) concentration (Nai) contribute to initiation, termination and modulation of phase-2 EADs, using two human ventricular myocyte models...
November 11, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27826330/management-of-patients-with-long-qt-syndrome
#13
REVIEW
Yongkeun Cho
Long QT syndrome (LQTS) is a rare cardiac channelopathy associated with syncope and sudden death due to torsades de pointes and ventricular fibrillation. Syncope and sudden death are frequently associated with physical and emotional stress. Management of patients with LQTS consists of life-style modification, β-blockers, left cardiac sympathetic denervation (LCSD), and implantable cardioverter-defibrillator (ICD) implantation. Prohibition of competitive exercise and avoidance of QT-prolonging drugs are important issues in life-style modification...
November 2016: Korean Circulation Journal
https://www.readbyqxmd.com/read/27816319/contribution-of-a-kcnh2-variant-in-genotyped-long-qt-syndrome-romano-ward-syndrome-under-double-mutations-and-acquired-long-qt-syndrome-under-heterozygote
#14
Yusuke Fujii, Yuichi Matsumoto, Kenshi Hayashi, Wei-Guang Ding, Yukinori Tomita, Daisuke Fukumoto, Yuko Wada, Mari Ichikawa, Keiko Sonoda, Junichi Ozawa, Takeru Makiyama, Seiko Ohno, Masakazu Yamagishi, Hiroshi Matsuura, Minoru Horie, Hideki Itoh
BACKGROUND: Long QT syndrome (LQTS) presents two clinical phenotypes, congenital and acquired forms. This study aims to evaluate the genetic contribution of a KCNH2 variant for the two LQTS phenotypes. METHODS: From 1996 to 2014, genetic screening for LQTS probands was performed for five major genes: KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 and 389 probands were found to be mutation carriers. We analyzed the clinical phenotypes of p.His492Tyr carriers in KCNH2. RESULTS: Heterozygous p...
November 2, 2016: Journal of Cardiology
https://www.readbyqxmd.com/read/27810088/the-promise-and-peril-of-precision-medicine-phenotyping-still-matters-most
#15
REVIEW
Jaeger P Ackerman, Daniel C Bartos, Jamie D Kapplinger, David J Tester, Brian P Delisle, Michael J Ackerman
We illustrate the work necessary to reverse course after identification of a KCNQ1 variant interpreted erroneously as causing long QT syndrome (LQTS) and to identify the true cause of a case of sudden death in the young. Surrogate genetic testing of a decedent's living brother identified a rare KCNQ1-V133I variant, which prompted an implantable cardioverter defibrillator and subsequent diagnosis of LQTS in other family members. Subsequently, this presumed LQT1 family came to our institution for further clinical evaluation and research-based investigations, including KCNQ1-V133I variant-specific analysis of the decedent, heterologous expression studies of KCNQ1-V133I, and a whole-exome molecular autopsy along with genomic triangulation using his unaffected parents' DNA...
October 8, 2016: Mayo Clinic Proceedings
https://www.readbyqxmd.com/read/27807201/molecular-pathophysiology-of-congenital-long-qt-syndrome
#16
REVIEW
M S Bohnen, G Peng, S H Robey, C Terrenoire, V Iyer, K J Sampson, R S Kass
Ion channels represent the molecular entities that give rise to the cardiac action potential, the fundamental cellular electrical event in the heart. The concerted function of these channels leads to normal cyclical excitation and resultant contraction of cardiac muscle. Research into cardiac ion channel regulation and mutations that underlie disease pathogenesis has greatly enhanced our knowledge of the causes and clinical management of cardiac arrhythmia. Here we review the molecular determinants, pathogenesis, and pharmacology of congenital Long QT Syndrome...
January 2017: Physiological Reviews
https://www.readbyqxmd.com/read/27805004/mir-19b-regulates-ventricular-action-potential-duration-in-zebrafish
#17
Alexander Benz, Mandy Kossack, Dominik Auth, Claudia Seyler, Edgar Zitron, Lonny Juergensen, Hugo A Katus, David Hassel
Sudden cardiac death due to ventricular arrhythmias often caused by action potential duration (APD) prolongation is a common mode of death in heart failure (HF). microRNAs, noncoding RNAs that fine tune gene expression, are frequently dysregulated during HF, suggesting a potential involvement in the electrical remodeling process accompanying HF progression. Here, we identified miR-19b as an important regulator of heart function. Zebrafish lacking miR-19b developed severe bradycardia and reduced cardiac contractility...
November 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27803431/m3-muscarinic-receptor-signaling-stabilizes-a-novel-mutant-human-ether-a-go-go-related-gene-channel-protein-via-phosphorylation-of-heat-shock-factor-1-in-transfected-cells
#18
Endang Mahati, Peili Li, Yasutaka Kurata, Nani Maharani, Nobuhito Ikeda, Shinji Sakata, Kazuyoshi Ogura, Junichiro Miake, Takeshi Aiba, Wataru Shimizu, Naoe Nakasone, Haruaki Ninomiya, Katsumi Higaki, Kazuhiro Yamamoto, Akira Nakai, Yasuaki Shirayoshi, Ichiro Hisatome
BACKGROUND: Long QT syndrome 2 (LQT2) is caused by mutations in the human ether-a-go-go-related gene (hERG). Most of its mutations give rise to unstable hERG proteins degraded by the proteasome. Recently, carbachol was reported to stabilize the wild-type hERG-FLAG via activation of the muscarinic type 3 receptor (M3-mAChR). Its action on mutant hERG-FLAG, however, remains uninvestigated.Methods and Results:A novel mutant hERG-FLAG carried 2 mutations: an amino acid substitution G572S and an in-frame insertion D1037_V1038insGD...
November 1, 2016: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/27768846/using-chemical-induced-gene-expression-in-cultured-human-cells-to-predict-chemical-toxicity
#19
Ruifeng Liu, Xueping Yu, Anders Wallqvist
Chemical toxicity is conventionally evaluated in animal models. However, animal models are resource intensive; moreover, they face ethical and scientific challenges because the outcomes obtained by animal testing may not correlate with human responses. To develop an alternative method for assessing chemical toxicity, we investigated the feasibility of using chemical-induced genome-wide expression changes in cultured human cells to predict the potential of a chemical to cause specific organ injuries in humans...
October 21, 2016: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/27765793/a-precision-medicine-approach-to-the-rescue-of-function-on-malignant-calmodulinopathic-long-qt-syndrome
#20
Worawan B Limpitikul, Ivy E Dick, David Tester, Nicole J Boczek, Pattraranee Limphong, Wanjun Yang, Myoung Hyun Choi, Jennifer Babich, Deborah DiSilvestre, Ronald J Kanter, Gordon F Tomaselli, Michael J Ackerman, David Yue
RATIONALE: Calmodulinopathies comprise a new category of potentially life-threatening genetic arrhythmia syndromes capable of producing severe long QT syndrome (LQTS) with mutations involving either CALM1, CALM2, or CALM3 The underlying basis of this form of LQTS is a disruption of Ca(2+)/CaM-dependent inactivation (CDI) of L-type Ca(2+) channels (LTCCs). OBJECTIVE: To gain insight into the mechanistic underpinnings of calmodulinopathies and devise new therapeutic strategies for the treatment of this form of LQTS...
October 20, 2016: Circulation Research
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