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Long qt syndrome

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https://www.readbyqxmd.com/read/29214556/influence-of-genetic-modifiers-on-sudden-cardiac-death-cases
#1
Tina Jenewein, Thomas Neumann, Damir Erkapic, Malte Kuniss, Marcel A Verhoff, Gerhard Thiel, Silke Kauferstein
Sequence variants in the ion channel genes KCNH2 and SCN5A may cause the cardiac disorder long QT syndrome (LQTS). This disorder is associated with incomplete penetrance and variable expression in KCNH2- or SCN5A-mutation carriers. Common genetic variants, if associated with a mutation, may affect the severity of this cardiac disorder. This study identified rare mutations in the cardiac ion channel genes KCNH2 and SCN5A in a SCD case, as well as in a LQTS-affected family with a history of SCD. Moreover, common variants were found to occur together within the same genes...
December 6, 2017: International Journal of Legal Medicine
https://www.readbyqxmd.com/read/29201009/in-vitro-and-in-silico-risk-assessment-in-acquired-long-qt-syndrome-the-devil-is-in-the-details
#2
REVIEW
William Lee, Monique J Windley, Jamie I Vandenberg, Adam P Hill
Acquired long QT syndrome, mostly as a result of drug block of the Kv11. 1 potassium channel in the heart, is characterized by delayed cardiac myocyte repolarization, prolongation of the T interval on the ECG, syncope and sudden cardiac death due to the polymorphic ventricular arrhythmia Torsade de Pointes (TdP). In recent years, efforts are underway through the Comprehensive in vitro proarrhythmic assay (CiPA) initiative, to develop better tests for this drug induced arrhythmia based in part on in silico simulations of pharmacological disruption of repolarization...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29197658/utilizing-the-genome-aggregation-database-computational-pathogenicity-prediction-tools-and-patch-clamp-heterologous-expression-studies-to-demote-previously-published-type-1-long-qt-syndrome-mutations-from-pathogenic-to-benign
#3
Daniel J Clemens, Anne R Lentino, Jamie D Kapplinger, Dan Ye, Wei Zhou, David J Tester, Michael J Ackerman
BACKGROUND: Mutations in the KCNQ1-encoded Kv7.1 potassium channel cause type 1 long QT syndrome (LQT1). It has been suggested that ∼10-20% of rare LQTS case-derived variants in the literature may have been published erroneously as LQT1-causative mutations and may be "false positives." OBJECTIVE: To determine which previously published KCNQ1 case variants are likely false positives. METHODS: A list of all published, case-derived KCNQ1 missense variants (MVs) was compiled...
November 29, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29194874/late-onset-severe-long-qt-syndrome
#4
Babken Asatryan, André Schaller, Deborah Bartholdi, Argelia Medeiros-Domingo
We report a case of torsades de pointes arrhythmia as the first manifestation of congenital Long QT syndrome in a 77-year-old man with family history of sudden unexplained death. This case illustrates the importance of vigilant clinical assessment and genetic counseling in families with sudden death in order to identify properly asymptomatic relatives at risk for cardiac events. It also demonstrates that Long QT syndrome can still manifest with potentially fatal arrhythmias late in life in previously asymptomatic elderly patients...
November 30, 2017: Annals of Noninvasive Electrocardiology
https://www.readbyqxmd.com/read/29183619/non-sustained-microvolt-level-t-wave-alternans-in-congenital-long-qt-syndrome-types-1-and-2
#5
Jovil A Kannampuzha, Prasanna Sengodan, Sravani Avula, Bartholomew White, Stephen J Ganocy, Peter J Leo, Elizabeth S Kaufman
BACKGROUND: Patients with long QT syndrome (LQTS) are predisposed to polymorphic ventricular tachycardia (VT) during adrenergic stimulation. Microvolt T-wave alternans (MTWA) is linked to vulnerability to VT in structural heart disease. The prevalence of non-sustained MTWA (NS-MTWA) in LQTS is unknown. METHODS: 31 LQT1, 42 LQT2, and 80 controls underwent MTWA testing during exercise. MTWA tests were classified per standardized criteria, and re-analyzed according to the modified criteria to account for NS-MTWA...
November 21, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29182204/-long-qt-syndrome-and-polymorphic-ventricular-tachycardia-due-to-hypopituitarism-report-of-one-case
#6
José Miguel García-Castro, Antonia García-Martín, Emilio Guirao-Arrabal, Pedro Luis Carrillo-Alascio
Symptoms of hypopituitarism are usually chronic and nonspecific, but rarely the disease can have acute and life threatening manifestations. We report a 53 years old female with a pituitary adenoma that was admitted to our hospital because of syncope. The electrocardiogram showed sinus bradycardia with a prolonged QT interval. Frequent runs of non-sustained polymorphic ventricular tachycardia were noted on telemetry. The patient had a history of severe acute headaches in the previous days and laboratory tests revealed severe secondary hypothyroidism, adrenal insufficiency and a decrease in pituitary hormones...
July 2017: Revista Médica de Chile
https://www.readbyqxmd.com/read/29174490/risk-of-cardiac-events-associated-with-antidepressant-therapy-in-patients-with-long-qt-syndrome
#7
Meng Wang, Barbara Szepietowska, Bronislava Polonsky, Scott McNitt, Arthur J Moss, Wojciech Zareba, David S Auerbach
Patients with long QT syndrome (LQTS) are at a high risk of cardiac events. Many patients with LQTS are treated with antidepressant drugs (ADs). We investigated the LQTS genotype-specific risk of recurrent cardiac arrhythmic events (CAEs) associated with AD therapy. The study included 59 LQT1 and 72 LQT2 patients from the Rochester-based LQTS Registry with corrected QT (QTc) prolongation and a history of AD therapy. Using multivariate Anderson-Gill models, we estimated the LQTS genotype-specific risk of recurrent CAEs (ventricular tachyarrhythmias, aborted cardiac arrest, or sudden cardiac death) associated with time-dependent ADs...
November 13, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/29173600/a-practical-approach-to-avoiding-cardiovascular-adverse-effects-of-psychoactive-medications
#8
REVIEW
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
https://www.readbyqxmd.com/read/29173400/channelopathies-as-causes-of-sudden-cardiac-death
#9
REVIEW
Peter J Schwartz, Michael J Ackerman, Arthur A M Wilde
This article reviews the main clinical aspects of 3 channelopathies: the long QT syndrome, the catecholaminergic polymorphic ventricular tachycardia, and the Brugada syndrome. The text summarizes our views on clinical presentation and diagnosis, on risk stratification, and on therapy. Special attention is given to the progress in the understanding of the genetic bases and on the growing impact of genetics on therapy, which, at least in the case of long QT syndrome, now allows gene-specific management.
December 2017: Cardiac Electrophysiology Clinics
https://www.readbyqxmd.com/read/29162896/%C3%AE-adrenergic-stimulation-augments-transmural-dispersion-of-repolarization-via-modulation-of-delayed-rectifier-currents-iks-and-ikr-in-the-human-ventricle
#10
C Kang, A Badiceanu, J A Brennan, C Gloschat, Y Qiao, N A Trayanova, I R Efimov
Long QT syndrome (LQTS) is an inherited or drug induced condition associated with delayed repolarization and sudden cardiac death. The cardiac potassium channel, IKr, and the adrenergic-sensitive cardiac potassium current, IKs, are two primary contributors to cardiac repolarization. This study aimed to elucidate the role of β-adrenergic (β-AR) stimulation in mediating the contributions of IKr and IKs to repolarizing the human left ventricle (n = 18). Optical mapping was used to measure action potential durations (APDs) in the presence of the IKs blocker JNJ-303 and the IKr blocker E-4031...
November 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29154691/optimal-screening-methods-to-detect-cardiac-disorders-in-athletes-an-evidence-based-review
#11
Zachary K Winkelmann, Ashley K Crossway
Reference/Citation:  Harmon KG, Zigman M, Drezner JA. The effectiveness of screening history, physical exam, and ECG to detect potentially lethal cardiac disorders in athletes: a systematic review/meta-analysis. J Electrocardiol. 2015;48(3):329-338. CLINICAL QUESTION:   Which screening method should be considered best practice to detect potentially lethal cardiac disorders during the preparticipation physical examination (PE) of athletes? DATA SOURCES:   The authors completed a comprehensive literature search of MEDLINE, CINAHL, Cochrane Library, Embase, Physiotherapy Evidence Database (PEDro), and SPORTDiscus from January 1996 to November 2014...
November 20, 2017: Journal of Athletic Training
https://www.readbyqxmd.com/read/29146210/novel-intracellular-transport-refractory-mutations-in-kcnh2-identified-in-patients-with-symptomatic-long-qt-syndrome
#12
Daisuke Fukumoto, Wei-Guang Ding, Yuko Wada, Yusuke Fujii, Mari Ichikawa, Koichiro Takayama, Megumi Fukuyama, Koichi Kato, Hideki Itoh, Takeru Makiyama, Mariko Omatsu-Kanbe, Hiroshi Matsuura, Minoru Horie, Seiko Ohno
BACKGROUND: Missense mutations in KCNH2, a gene encoding the Kv11.1 channel, cause long QT syndrome (LQTS) type 2 primarily by disrupting the intracellular transport of Kv11.1 to the plasma membrane. The present study aimed to clarify the functional changes by two novel KCNH2 missense mutations. METHODS: We performed genetic screening of three unrelated symptomatic LQTS probands with family histories of cardiac symptoms. Chinese hamster ovary cells were transfected with wild-type (WT) and/or mutant KCNH2 plasmid and examined by patch-clamp technique...
November 13, 2017: Journal of Cardiology
https://www.readbyqxmd.com/read/29141847/t-wave-morphology-analysis-to-detect-high-risk-in-long-qt-syndrome
#13
EDITORIAL
Elizabeth S Kaufman, Isabelle Deschênes
No abstract text is available yet for this article.
November 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29141844/architectural-t-wave-analysis-and-identification-of-on-therapy-breakthrough-arrhythmic-risk-in-type-1-and-type-2-long-qt-syndrome
#14
Alan Sugrue, Ram K Rohatgi, Peter A Noseworthy, Vaclav Kremen, J Martijn Bos, Bo Qiang, Yehu Sapir, Zachi I Attia, Christopher G Scott, Peter Brady, Samuel J Asirvatham, Paul A Friedman, Michael J Ackerman
BACKGROUND: Although the hallmark of long-QT syndrome (LQTS) is abnormal cardiac repolarization, there are varying degrees of phenotypic expression and arrhythmic risk. Our aim was to evaluate the performance of a morphological T-wave analysis program in defining breakthrough LQTS arrhythmic risk beyond the QTc value. METHODS AND RESULTS: We analyzed 407 genetically confirmed patients with LQT1 (n=246; 43% men) and LQT2 (n=161; 41% men) over the mean follow-up period of 6...
November 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29133340/effects-of-hawthorn-crataegus-pentagyna-leaf-extract-on-electrophysiologic-properties-of-cardiomyocytes-derived-from-human-cardiac-arrhythmia-specific-induced-pluripotent-stem-cells
#15
Sara Pahlavan, Marziyeh Shalchi Tousi, Mahdi Ayyari, Abolfazl Alirezalu, Hassan Ansari, Tomo Saric, Hossein Baharvand
Cardiac arrhythmias are major life-threatening conditions. The landmark discovery of induced pluripotent stem cells has provided a promising in vitro system for modeling hereditary cardiac arrhythmias as well as drug development and toxicity testing. Nowadays, nutraceuticals are frequently used as supplements for cardiovascular therapy. Here we studied the cardiac effects of hawthorn (Crataegus pentagyna) leaf extract using cardiomyocytes (CMs) differentiated from healthy human embryonic stem cells, long QT syndrome type 2 (LQTS2), and catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) patient-specific induced pluripotent stem cells...
November 13, 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/29127493/late-sodium-current-associated-cardiac-electrophysiological-and-mechanical-dysfunction
#16
REVIEW
Shandong Yu, Gang Li, Christopher L-H Huang, Ming Lei, Lin Wu
Late sodium current (INaL) is a small sustained inward current observed during the cardiac action potential plateau phase following decay of the early peak INa. The endogenous INaL is relatively small in normal hearts but exerts functionally significant effects on cardiomyocyte repolarization with potentially pro-arrhythmic effects in hearts with reduced repolarization reserve. Enhanced INa,L occurs in long QT syndrome 3 (LQTS 3) patients, and under a number of pathological and pharmacological cardiovascular conditions, including bradycardia, myocardial ischemia, reperfusion injury, and heart failure...
November 10, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/29121487/risk-of-cardiac-events-in-long-qt-syndrome-patients-when-taking-antiseizure-medications
#17
David S Auerbach, Yitschak Biton, Bronislava Polonsky, Scott McNitt, Robert A Gross, Robert T Dirksen, Arthur J Moss
Many antiseizure medications (ASMs) affect ion channel function. We investigated whether ASMs alter the risk of cardiac events in patients with corrected QT (QTc) prolongation. The study included people from the Rochester-based Long QT syndrome (LQTS) Registry with baseline QTc prolongation and history of ASM therapy (n = 296). Using multivariate Anderson-Gill models, we assessed the risk of recurrent cardiac events associated with ASM therapy. We stratified by LQTS genotype and predominant mechanism of ASM action (Na(+) channel blocker and gamma-aminobutyric acid modifier...
October 20, 2017: Translational Research: the Journal of Laboratory and Clinical Medicine
https://www.readbyqxmd.com/read/29118886/polymorphic-ventricular-tachycardia-secondary-to-subarachnoid-haemorrhage-a-rare-occurrence-in-the-setting-of-normal-qtc
#18
Siddharth Paresh Shah, Priyanka Pitroda, Kinner Patel, Rahul Chandak, Timothy Ford
Subarachnoid hemorrhage (SAH) is a neurologic emergency associated with high mortality rate. Polymorphic ventricular tachycardia (VT) is a rare arrhythmia. It can occur in any setting of a long QT interval and bradycardia. This may result from a cardiomyopathy (both ischemic and non-ischemic), acute coronary ischemia, congenital long QT syndrome, electrolyte disturbances and cerebrovascular diseases. We report a rare case of polymorphic VT of unclear etiology with a normal corrected QT, likely secondary to SAH...
October 2017: Cardiology Research
https://www.readbyqxmd.com/read/29104543/simultaneous-quantification-of-spatially-discordant-alternans-in-voltage-and-intracellular-calcium-in-langendorff-perfused-rabbit-hearts-and-inconsistencies-with-models-of-cardiac-action-potentials-and-ca-transients
#19
Ilija Uzelac, Yanyan C Ji, Daniel Hornung, Johannes Schröder-Scheteling, Stefan Luther, Richard A Gray, Elizabeth M Cherry, Flavio H Fenton
Rationale: Discordant alternans, a phenomenon in which the action potential duration (APDs) and/or intracellular calcium transient durations (CaDs) in different spatial regions of cardiac tissue are out of phase, present a dynamical instability for complex spatial dispersion that can be associated with long-QT syndrome (LQTS) and the initiation of reentrant arrhythmias. Because the use of numerical simulations to investigate arrhythmic effects, such as acquired LQTS by drugs is beginning to be studied by the FDA, it is crucial to validate mathematical models that may be used during this process...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29101013/the-congenital-long-qt-syndrome-type-3-an-update
#20
REVIEW
Andrés Ricardo Pérez-Riera, Raimundo Barbosa-Barros, Rodrigo Daminello Raimundo, Marianne Penachini da Costa de Rezende Barbosa, Isabel Cristina Esposito Sorpreso, Luiz Carlos de Abreu
Congenital long QT syndrome type 3 (LQT3) is the third in frequency compared to the 15 forms known currently of congenital long QT syndrome (LQTS). Cardiac events are less frequent in LQT3 when compared with LQT1 and LQT2, but more likely to be lethal; the likelihood of dying during a cardiac event is 20% in families with an LQT3 mutation and 4% with either an LQT1 or an LQT2 mutation. LQT3 is consequence of mutation of gene SCN5A which codes for the Nav1.5 Na(+) channel α-subunit and electrocardiographically characterized by a tendency to bradycardia related to age, prolonged QT/QTc interval (mean QTc value 478 ± 52 ms), accentuated QT dispersion consequence of prolonged ST segment, late onset of T wave and frequent prominent U wave because of longer repolarization of the M cell across left ventricular wall...
October 31, 2017: Indian Pacing and Electrophysiology Journal
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