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'Long QT Syndrome' (8910)


Dec
1969

Interactions of drug molecules with lipid membranes play crucial role in their accessibility of cellular targets and can be an important predictor of their therapeutic and safety profiles. Very little is known about spatial localization of various drugs in the lipid bilayers, their active form (ionization state) or translocation rates and therefore potency to bind to different sites in membrane proteins. All-atom molecular simulations may help to map drug partitioning kinetics and thermodynamics, thus providing in-depth assessment of drug lipophilicity.

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Feb
2018

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.

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Feb
2018

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.

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Dec
1969

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.

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Feb
2018

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.

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Feb
2018

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.

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Feb
2018

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.

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Feb
2018

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.

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Feb
2018

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. In turn, these molecular insights led to the development and increased utilization of clinically impactful genetic testing for congenital long QT syndrome.

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Feb
2018

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).
To assess the association of APB-TWI with TdP history and with microvolt TWA.

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Feb
2018

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.

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Feb
2018

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.
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.

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Jan
2018

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.

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Mar
2018

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.

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Feb
2018

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).

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Mar
2018

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).
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).

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Feb
2018

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. 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.

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Feb
2018

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.

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Feb
2018

The frequency of arrhythmic death developing without a structural cardiac disease is higher in women. Also female gender is an independent risk factor regarding developing Torsades des Pointes. Several studies have been conducted on the effects of physiological and therapeutic sex hormones on cardiac conduction system.

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Jan
2018

Antazoline is a first-generation antihistamine with antiarrhythmic properties. This study examines potential electrophysiological effects of antazoline in short-QT-syndrome (SQTS) and long-QT-syndrome (LQTS).
Sixty-five rabbit hearts were Langendorff-perfused.

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Jan
2018

T-wave alternans (TWA) and irregular beat-to-beat T-wave variability or T-wave lability (TWL), the ECG manifestations of action potential duration (APD) alternans and variability, are precursors of ventricular arrhythmias in long QT syndromes. TWA and TWL in patients tend to occur at normal heart rates and are usually potentiated by bradycardia. Whether or how TWA and TWL at normal or slow heart rates are causally linked to arrhythmogenesis remains unknown.

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Jan
2018

Jervell and Lange-Nielsen syndrome is an autosomal recessive disorder caused by mutations in KCNQ1 or KCNE1 genes. The disease is characterized by sensorineural hearing loss and long QT syndrome.
Here we present a 3.

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Jan
2018

Pain medication and long QT syndrome.

Korean J Pain 2018 Jan 2;31(1):3-9. Epub 2018 Jan 2.
Christoph Klivinyi, Helmar Bornemann-Cimenti
Long QT syndrome is a cardiac repolarization disorder and is associated with an increased risk of torsades de pointes. The acquired form is most often attributable to administration of specific medications and/or electrolyte imbalance. This review provides insights into the risk for QT prolongation associated with drugs frequently used in the treatment of chronic pain.

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Jan
2018

The human ether-a-go-go-related gene (hERG) encodes the α subunit of a rapidly activating delayed-rectifier potassium (I) channel. Mutations of the hERG cause long QT syndrome type 2 (LQT2). Acetylation of lysine residues occurs in a subset of non-histone proteins and this modification is controlled by both histone acetyltransferases and deacetylases (HDACs).

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Jan
2018

Trait-like sensitivity to stress in long QT syndrome patients has been documented previously. In addition, mental stress has been associated with symptomatic status of long QT syndrome. We examined whether the symptomatic type 1 long QT syndrome patients would be more sensitive to mental stress compared to asymptomatic patients and whether there would be differences in task-related physiological stress reactions between type 1 long QT syndrome patients and healthy individuals.

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Jan
2018

Lowered costs of genomic sequencing facilitate analyzing large segments of genetic data. Ethical debate has focused on whether and what kind of incidental or secondary findings (SFs) to report, and how to obtain valid informed consent. However, people's support needs after receiving SFs have received less attention.

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Dec
1969

Arsenic trioxide (ATO) is a known anti-acute promyelocytic leukemia (APL) reagent, whose clinical applications are limited by its serious cardiac toxicity and fatal adverse effects, such as sudden cardiac death resulting from long QT syndrome (LQTS). The mechanisms of cardiac arrhythmia due to ATO exposure still need to be elucidated. Long non-coding RNAs (lncRNAs) are emerging as major regulators of various pathophysiological processes.

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Dec
1969

A 32-year-old woman with a past medical history of paroxysmal atrial fibrillation, long QT syndrome, and implantation of an automatic iimplantable cardioverter-defibrillator (AICD) following cardiac arrest presented with disabling symptoms of paroxysmal atrial fibrillation due to recurrent AICD shocks. Before curative ablation, transesophageal echocardiography was performed to assess for existing thrombi. This is a rare case of successful resolution with apixaban of a massive left atrial appendage thrombus due to non-rheumatic atrial fibrillation that was successfully treated with apixaban.

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Dec
2017

Long QT syndrome (LQTS) is the most common cardiac ion channelopathy and has been found to be responsible for approximately 10% of sudden infant death syndrome (SIDS) cases. Despite increasing use of broad panels and now whole exome sequencing (WES) in the investigation of SIDS, the probability of identifying a pathogenic mutation in a SIDS victim is low. We report a family-based study who are afflicted by recurrent SIDS in which several members harbor a variant, p.

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Jan
2018

A 27-year-old female was seen for long QT syndrome. She was found to be a carrier of two variants, KCNQ1 Val162Met and KCNH2 Ser55Leu, and both were annotated as pathogenic by a diagnostic laboratory in part because of sequence proximity to other known pathogenic variants.
To assess the relationship between both the KCNQ1 and KCNH2 variants and clinical significance using protein structure, in vitro functional assays, and familial segregation.

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Jan
2018

A significant antiarrhythmic potential of ryanodine receptor inhibition was reported in experimental studies. The aim of the present study was to assess potential antiarrhythmic effects of dantrolene in an experimental whole-heart model of drug-induced long-QT syndrome (LQTS).
In 12 isolated rabbit hearts, long-QT-2-syndrome was simulated by infusion of erythromycin (300 μM).

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Jan
2018

Subcutaneous implantable cardioverter-defibrillator (SICD) shows promise for select patients at risk of sudden death. However, patients need to pass an electrocardiographic (ECG) screening (ECG-S) test before they can receive an SICD. Predictors of ECG-S failure in children are unclear.

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Jan
2018

Rare high arousal negative emotions are known triggers of sudden death in individuals with preexisting heart disease. Whether everyday fluctuations in emotional arousal influence arrhythmia risk is unknown.
We studied 160 patients with the congenital Long QT Syndrome (LQTS), 199 patients with coronary artery disease, and two groups of matched healthy volunteers (n=53 and 50, respectively).

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Jan
2018

Fluid movement within the heart generates substantial shear forces, but the effect of this mechanical stress on the electrical activity of the human heart has not been examined. The fast component of the delayed rectifier potassium currents responsible for repolarization of the cardiac action potential, Ikr, is encoded by the hERG channel. Here, we exposed hERG1a channel-expressing HEK293T cells to laminar shear stress (LSS) and observed that this mechanical stress increased the whole-cell current by 30%-40%.

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Jan
2018

Since the introduction of regulatory drug approval guidance on the evaluation of QT interval prolongation, an increasing number of drug monographs has included cautions on the risk of QT prolongation. For example, QT prolongation is mentioned in the Canadian product monographs of 29 drugs commonly seen in oncology practice. This presents two major challenges.

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Jan
2018

Today, understanding the true risk of adverse events in long-QT syndrome (LQTS) populations may be extremely complex and potentially dependent on many factors such as the affected gene, mutation location, degree of QTc prolongation, age, sex, and other yet unknown factors. In this context, risk stratification by genotype in LQTS patients has been extremely difficult, also during exercise practice, especially due to the lack of studies that would lead to a better understanding of the natural history of each mutation and its impact upon athletes. The creation of individualized guidelines for sport participation is a goal yet to be achieved not only due to the complexity of genotype effect on the phenotype in this patient population, but also due to penetrance in genotype-positive patients.

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Jan
2018

QT-interval variations in response to exercise-induced increases in heart rate have been reported in children and adults in the diagnosis of long QT syndrome (LQTS). A quick standing challenge has been proposed as an alternative provocative test in adults, with no pediatric data yet available.
A standing test was performed in 100 healthy children (mean age, 9.

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Dec
1969

Genealogy and molecular genetic studies of a Swedish river valley population resulted in a large pedigree, showing that the hereditary hemochromatosis (HH)C282Y mutation is inherited with other recessive disorders such as Wilson´s disease (WND), a rare recessive disorder of copper overload. The population also contain individuals with the Swedish long QT syndrome (LQTS1) founder mutation (/p.Y111C) which in homozygotes causes the Jervell & Lange Nielsen syndrome (JLNS) and hearing loss (HL).

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Dec
2017

Congenital long QT syndrome (LQTS) can cause ventricular arrhythmic events with syncope and sudden death resulting from malignant torsades de pointes (TdP) followed by ventricular fibrillations (VFs). However, the syndrome is often overlooked prior to the development of arrhythmic events in patients with congenital heart diseases demonstrating right bundle branch block on electrocardiogram (ECG). We present a case of an adult patient with congenital heart disease who developed VFs postoperatively, potentially due to his mutation in a LQTS related gene, which was not identified on preoperative assessment due to incomplete evaluation of his family history.

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Dec
2017

Due to its availability, atenolol is the primary beta-blocker used in Australia for children with long QT syndrome. There is limited data on long-term follow-up of its use.
A single-tertiary-center, retrospective, observational study investigating all children and adolescents who had genetically proven long QT syndrome type 1 (LQT1) and type 2 (LQT2) was conducted.

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Dec
2017

Syncope in patients with inherited arrhythmias.

J Arrhythm 2017 Dec 6;33(6):572-578. Epub 2017 Oct 6.
Yukiko Nakano, Shimizu Wataru
Syncope, a common symptom of cerebral ischemia often shows a multifactorial etiopathogenesis. Although inherited arrhythmias causing syncope is uncommon, such an occurrence could be a warning sign preceding cardiac arrest. Long QT syndrome (LQTS) is a typical inherited arrhythmia causing syncope in children.

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Dec
2017

The Brugada syndrome (BrS) is associated with increased risk of ventricular arrhythmias and sudden cardiac death. It generates genetically mediated arrhythmias posing a true pathophysiological challenge. In search of the similarities between BrS and long QT syndrome some novel insights are suggested.

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Dec
2017

Sports eligibility and disqualification of patients with cardiac diseases are important considerations for adult and pediatric cardiologists. The 2005 guidelines that addressed this issue have recently been revised and updated, and the new guidelines advocate for a shared decision-making approach in which the well-informed athlete and family participate in the discussion. In this review, we focus on the benefits of sports participation and review the revised guidelines related to sports participation in patients with channelopathies and cardiomyopathies.

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Dec
2017

Drug-induced prolongation of the corrected QT interval (QTc) may lead to serious and potentially life-threatening ventricular tachyarrhythmia, such as torsades de pointes (Tdp), which is worthy of clinical attention. Here, we report 1 case of Tdp after a coadministration of fluoxetine and amiodarone.
A 62-year-old Chinese male who placed with the implanted cardioverter-defibrillator (ICD) appeared the QTc prolongation and Tdp after the concurrent administration of fluoxetine and amiodarone.

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Dec
2017

Short QT syndrome (SQTS) is a rare and life-threatening arrhythmogenic syndrome characterized by abbreviated repolarization. Hydroquinidine (HQ) prolongs the QT interval in SQTS patients, although whether it reduces cardiac events is currently unknown.
This study investigated whether long-term treatment with HQ reduces the occurrence of life-threatening arrhythmic events (LAE) (cardiac arrest or sudden cardiac death) in SQTS patients.

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Dec
2017

In 2016, the Children's Hospital of Eastern Ontario (CHEO) announced the settlement of its patent lawsuit against US-based Transgenomic, Inc. At issue in the case was CHEO's ability to test for gene mutations associated with long QT syndrome (LQTS) that are described in Transgenomic's patents. CHEO challenged the patents as invalid, and Transgenomic ultimately agreed to license them on a royalty-free basis to CHEO and other healthcare institutions for LQTS testing and research.

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