11,180 results match your criteria Long QT Syndrome


Loperamide-induced ventricular tachycardia storm.

Br J Cardiol 2021 13;28(4):46. Epub 2021 Oct 13.

Consultant Cardiologist/Electrophysiologist Northern General Hospital, Sheffield, S5 7AU.

Loperamide is an over-the-counter, peripherally-acting, -opioid receptor agonist commonly used in the treatment of diarrhoea. It has increasingly been recognised as a potential drug of misuse, having previously been thought to have low potential for abuse owing to its low bioavailability and poor penetration of the central nervous system. High doses can result in life-threatening cardiac-toxicity. Read More

View Article and Full-Text PDF
October 2021

Latent Causes of Sudden Cardiac Arrest.

JACC Clin Electrophysiol 2022 Jun;8(6):806-821

Center for Cardiovascular Innovation, Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada; Victorian Heart Institute, Monash University, Clayton, Victoria, Australia.

Inherited arrhythmia syndromes are a common cause of apparently unexplained cardiac arrest or sudden cardiac death. These include long QT syndrome and Brugada syndrome, with a well-recognized phenotype in most patients with sufficiently severe disease to lead to cardiac arrest. Less common and typically less apparent conditions that may not be readily evident include catecholaminergic polymorphic ventricular tachycardia, short QT syndrome and early repolarization syndrome. Read More

View Article and Full-Text PDF

Resuscitated Sudden Cardiac Arrest of a Neonate with Congenital LQT Syndrome-Associated Torsades de Pointes: A Case Report and Literature Review.

J Cardiovasc Dev Dis 2022 Jun 9;9(6). Epub 2022 Jun 9.

Department of Pediatric Cardiology, Mackay Children's Hospital, Taipei 104217, Taiwan.

Sudden infant death syndrome (SIDS), the most common cause of infant death in developed countries, is attributed to diverse trigger factors. Malignant cardiac dysrhythmias are potentially treatable etiologies, and congenital long QT syndrome (LQTS) is the most common cardiac ionic channelopathy confronted. β-Blockers or class Ib agents are the drugs of choice for the control of arrhythmias, and an implantable cardioverter defibrillator (ICD) should be considered for secondary prevention in survivors of lethal cardiac death. Read More

View Article and Full-Text PDF

CONGENITAL LONG QT SYNDROME: A SYSTEMATIC REVIEW.

Acta Clin Croat 2021 Dec;60(4):739-748

1School of Medicine, University of Zagreb, Zagreb, Croatia; 2Sveti Duh University Hospital, Zagreb, Croatia; 3Merkur University Hospital, Zagreb, Croatia.

Congenital long QT syndrome (LQTS) is a disorder of myocardial repolarization defined by a prolonged QT interval on electrocardiogram (ECG) that can cause ventricular arrhythmias and lead to sudden cardiac death. LQTS was first described in 1957 and since then its genetic etiology has been researched in many studies, but it is still not fully understood. Depending on the type of monogenic mutation, LQTS is currently divided into 17 subtypes, with LQT1, LQT2, and LQT3 being the most common forms. Read More

View Article and Full-Text PDF
December 2021

Initiation of ventricular arrhythmia in the acquired long QT syndrome.

Cardiovasc Res 2022 Jun 21. Epub 2022 Jun 21.

Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK.

Aims: Long QT syndrome (LQTS) carries a risk of life-threatening polymorphic ventricular tachycardia (Torsades de Pointes, TdP) and is a major cause of premature sudden cardiac death. TdP is induced by R-on-T premature ventricular complexes (PVCs), thought to be generated by cellular early-afterdepolarisations (EADs). However, EADs in tissue require cellular synchronisation, and their role in TdP induction remains unclear. Read More

View Article and Full-Text PDF

Kalium channelrhodopsins are natural light-gated potassium channels that mediate optogenetic inhibition.

Nat Neurosci 2022 Jun 20. Epub 2022 Jun 20.

Center for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA.

Channelrhodopsins are used widely for optical control of neurons, in which they generate photoinduced proton, sodium or chloride influx. Potassium (K) is central to neuron electrophysiology, yet no natural K-selective light-gated channel has been identified. Here, we report kalium channelrhodopsins (KCRs) from Hyphochytrium catenoides. Read More

View Article and Full-Text PDF

Implantable defibrillators in primary prevention of genetic arrhythmias. A shocking choice?

Eur Heart J 2022 Jun 21. Epub 2022 Jun 21.

Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy.

Many previously unexplained life-threatening ventricular arrhythmias and sudden cardiac deaths (SCDs) in young individuals are now recognized to be genetic in nature and are ascribed to a growing number of distinct inherited arrhythmogenic diseases. These include hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia (VT), and short QT syndrome. Because of their lower frequency compared to coronary disease, risk factors for SCD are not very precise in patients with inherited arrhythmogenic diseases. Read More

View Article and Full-Text PDF

[The long-term efficacy of left cardiac sympathetic denervation in long QT syndrome].

Zhonghua Xin Xue Guan Bing Za Zhi 2022 Jun;50(6):556-562

Department of Cardiology, Peking University People's Hospital, Beijing 100044, China.

To investigate the long-term efficacy and safety of left cardiac sympathetic denervation(LCSD) for long QT syndrome(LQTS) patients with either recurrence on drug therapy intolerance/refusal. This study was a retrospective cohort study. The cases selected from 193 patients with LQTS who were enrolled in the Chinese Channelopathy Registry Study from November 1999 to November 2012. Read More

View Article and Full-Text PDF

Spectrum and Prevalence of Side Effects and Complications with Guideline Directed Therapies for Congenital Long QT Syndrome.

Heart Rhythm 2022 Jun 13. Epub 2022 Jun 13.

Department of Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, Minnesota; Department of Cardiovascular Medicine (Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic), Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), Mayo Clinic, Rochester, Minnesota. Electronic address:

Background: Beta blockers (BBs), sodium channel blockers (SCBs), left cardiac sympathetic denervation (LCSD), and implantable cardioverter defibrillators (ICDs) are used to prevent or counter long QT syndrome (LQTS)-triggered syncope, seizures, and sudden cardiac death (SCD). The spectrum and extent of side effects/complications associated with these guideline-directed therapies (GDTs) remain unknown.

Objective: Identify the types/prevalence of treatment-associated side effects/complications for patients with the most common LQTS subtypes following GDT. Read More

View Article and Full-Text PDF

Long QT Syndrome: To Exercise Safely or Not To Exercise, That's the Question!!!

Eur J Prev Cardiol 2022 Jun 16. Epub 2022 Jun 16.

Exercise Cardiology Research Group (CardioEx), Hospital de Clínicas, Rio Grade do Sul Federal University, Porto Alegre, RS, Brazil.

View Article and Full-Text PDF

Molecular Approach of Hereditary Arrhythmias, Long QT Syndrome, and Arrhythmogenic Right Ventricular Cardiomyopathy.

Anatol J Cardiol 2022 06;26(6):460-465

Department of Medical Genetics, University of Health Sciences, Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Ankara, Turkey.

Background: Hereditary cardiac arrhythmias result from mutations in various genes encoding ion channels. One major channelopathy is long QT syndrome, which has excel- lent genetic and clinical heterogeneity. Arrhythmogenic right ventricular cardiomyopa- thy, another hereditary arrhythmia type, also shows high genetic heterogeneity and variable expressivity. Read More

View Article and Full-Text PDF

Long QT Syndrome, Pregnancy and Nonselective β-blockers: Efficacious for Mom and Safe for Baby?

Heart Rhythm 2022 Jun 11. Epub 2022 Jun 11.

Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN. Electronic address:

View Article and Full-Text PDF

Human induced pluripotent stem cell line ZZUNEUi027-A generated from a long QT syndrome patient with a heterozygous KCNH2 (c. 128 A > G) mutant.

Stem Cell Res 2022 Jun 7;63:102836. Epub 2022 Jun 7.

Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China. Electronic address:

Long QT syndrome is one of the most common hereditary arrhythmias. Mutations in KCNH2 can cause long QT syndrome type 2 (LQT2). In this study, we generated a human induced pluripotent stem cell line ZZUNEUi027-A from a LQT2 female patient with c. Read More

View Article and Full-Text PDF

The genetics of drug-induced QT prolongation: evaluating the evidence for pharmacodynamic variants.

Pharmacogenomics 2022 Jun 14;23(9):543-557. Epub 2022 Jun 14.

Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, MI 48109, USA.

Drug-induced long QT syndrome (diLQTS) is an adverse effect of many commonly prescribed drugs, and it can increase the risk for lethal ventricular arrhythmias. Genetic variants in pharmacodynamic genes have been associated with diLQTS, but the strength of the evidence for each of those variants has not yet been evaluated. Therefore, the purpose of this review was to evaluate the strength of the evidence for pharmacodynamic genetic variants associated with diLQTS using a novel, semiquantitative scoring system modified from the approach used for congenital LQTS. Read More

View Article and Full-Text PDF

Bidirectional Ventricular Tachycardia: Challenges and Solutions.

Vasc Health Risk Manag 2022 7;18:397-406. Epub 2022 Jun 7.

Division of Cardiology, Department of Medicine, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada.

Bidirectional ventricular tachycardia (BiVT) is a rare form of ventricular tachycardia that manifests on surface electrocardiogram by dual QRS morphologies alternating on a beat-to-beat basis. It was first reported in the 1920s as a complication of digoxin, and since then, it has been reported in other conditions including fulminant myocarditis, sarcoidosis, catecholaminergic polymorphic ventricular tachycardia, and Andersen-Tawil syndrome. The mechanism for BiVT is not as well known as other forms of ventricular tachycardia but appears to include typical mechanisms including triggered activity from afterdepolarizations, abnormal automaticity, or reentry. Read More

View Article and Full-Text PDF

Arrhythmic Storm Due to ICD Atrial Lead Malfunction.

JACC Case Rep 2022 Apr 6;4(7):438-442. Epub 2022 Apr 6.

Cardiovascular Research Centre OLV, Aalst, Belgium.

We describe the case of a young woman with a dual-chamber implantable cardioverter-defibrillator for long-QT syndrome who was referred to our emergency department (Cardiovascular Research Centre of Aalst, Belgium) because of an "arrhythmic storm" caused by atrial lead fracture. This case highlights the importance of the correct choice of both the device type and the pacing modality. (). Read More

View Article and Full-Text PDF

A massively parallel assay accurately discriminates between functionally normal and abnormal variants in a hotspot domain of KCNH2.

Am J Hum Genet 2022 Jun 2. Epub 2022 Jun 2.

Mark Cowley Lidwill Research Program in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; School of Clinical Medicine, UNSW Sydney, Darlinghurst, NSW, Australia. Electronic address:

Many genes, including KCNH2, contain "hotspot" domains associated with a high density of variants associated with disease. This has led to the suggestion that variant location can be used as evidence supporting classification of clinical variants. However, it is not known what proportion of all potential variants in hotspot domains cause loss of function. Read More

View Article and Full-Text PDF

A calibrated functional patch-clamp assay to enhance clinical variant interpretation in KCNH2-related long QT syndrome.

Am J Hum Genet 2022 Jun 3. Epub 2022 Jun 3.

Mark Cowley Lidwill Research Program in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; School of Clinical Medicine, UNSW Sydney, Darlinghurst, NSW, Australia. Electronic address:

Modern sequencing technologies have revolutionized our detection of gene variants. However, in most genes, including KCNH2, the majority of missense variants are currently classified as variants of uncertain significance (VUSs). The aim of this study was to investigate the utility of an automated patch-clamp assay for aiding clinical variant classification in KCNH2. Read More

View Article and Full-Text PDF

[When QT gets longer].

G Ital Cardiol (Rome) 2022 06;23(6):423

Dipartimento di Cardiologia, Ospedale di Cremona, Cremona - Università degli Studi, Brescia.

View Article and Full-Text PDF

Pseudohypoparathyroidism: a diagnosis to consider once a PTH elevation is detected.

Acta Biomed 2022 06 6;93(S3):e2022194. Epub 2022 Jun 6.

.

Background And Aim: Pseudohypoparathyroidism (PHP) is a rare disease, which can occur in the youth, characterized by hypocalcemia and hyperphosphatemia due to resistance to parathyroid hormone (PTH) in target organs. This condition encompasses different conditions which differ between one another by different clinical, biochemically, and genetic features.

Methods: Herein we report the clinical history of a boy with PHP1B with an interesting clinical presentation. Read More

View Article and Full-Text PDF

Long QT and Hearing Loss in High-Risk Infants Prospective Study Registry.

Pediatr Cardiol 2022 Jun 3. Epub 2022 Jun 3.

The MEDNAX Center for Research, Education, Quality and Safety, 1301 Concord Ter, Sunrise, FL, 33323, USA.

The objective of this study is to determine the prevalence of an abnormal electrocardiogram showing a prolonged QTc greater than 450 ms in infants with unilateral or bilateral sensorineural hearing loss. We conducted a prospective study of healthy term infants (≥37 weeks gestational age) who failed their newborn auditory brainstem response hearing screen, were seen by an audiologist and diagnosed as having sensorineural hearing loss during follow-up to 1 year of age. In infants with a diagnosis of hearing loss, we collected a detailed family history and performed an ECG between 2 and 6 months of age. Read More

View Article and Full-Text PDF

Clinician Responses to a Clinical Decision Support Advisory for High Risk of Torsades de Pointes.

J Am Heart Assoc 2022 Jun 3;11(11):e024338. Epub 2022 Jun 3.

College of Pharmacy University of Utah Salt Lake City UT.

Background Torsade de pointes (TdP) is a potentially fatal cardiac arrhythmia that is often drug induced. Clinical decision support (CDS) may help minimize TdP risk by guiding decision making in patients at risk. CDS has been shown to decrease prescribing of high-risk medications in patients at risk of TdP, but alerts are often ignored. Read More

View Article and Full-Text PDF

Vandetanib-Induced Hyponatremia and Torsades De Pointes: A Case Report.

Cureus 2022 Apr 28;14(4):e24556. Epub 2022 Apr 28.

Cardiovascular Disease, BronxCare Health System/Icahn School of Medicine at Mount Sinai, New York City, USA.

Medullary thyroid cancer (MTC) is a neuroendocrine tumor of the parafollicular cells of the thyroid gland. The prognosis is very poor in patients with advanced MTC. Vandetanib was approved for advanced MTC after randomized control trials showed that it had therapeutic efficacy and considerably prolonged progression-free survival. Read More

View Article and Full-Text PDF

Deciphering Common Long QT Syndrome Using CRISPR/Cas9 in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Front Cardiovasc Med 2022 13;9:889519. Epub 2022 May 13.

Department of Cardiovascular, Ningbo Institute of Innovation for Combined Medicine and Engineering, Ningbo, China.

From carrying potentially pathogenic genes to severe clinical phenotypes, the basic research in the inherited cardiac ion channel disease such as long QT syndrome (LQTS) has been a significant challenge in explaining gene-phenotype heterogeneity. These have opened up new pathways following the parallel development and successful application of stem cell and genome editing technologies. Stem cell-derived cardiomyocytes and subsequent genome editing have allowed researchers to introduce desired genes into cells in a dish to replicate the disease features of LQTS or replace causative genes to normalize the cellular phenotype. Read More

View Article and Full-Text PDF

Revisiting QT prolongation in acute rheumatic fever - Relevance for hydroxychloroquine treatment.

Int J Cardiol 2022 Sep 26;362:93-96. Epub 2022 May 26.

Green Lane Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand. Electronic address:

In-vitro evidence suggests hydroxychloroquine could be a potential immunomodulator for the inflammatory carditis of acute rheumatic fever (ARF). Hydroxychloroquine used as an anti-inflammatory agent has a low side effect profile but its use in the Covid-19 pandemic raised concerns about QTc interval prolongation and cardiac arrhythmias. The prolongation of QTc in ARF appears benign but has not been widely studied. Read More

View Article and Full-Text PDF
September 2022

Pharmacological characterisation of electrocardiogram J-T interval in conscious Guinea pigs.

Eur J Pharmacol 2022 Jul 29;927:175065. Epub 2022 May 29.

Watarase Research Center, Kyorin Pharmaceutical Co., Ltd., 1848, Nogi, Nogi-machi, Shimotsuga-gun, Tochigi, 329-0114, Japan.

Drug-induced human ether-à-go-go-related gene (hERG) channel block and QT interval prolongation increase torsade de pointes (TdP) risk. However, some drugs block hERG channels and prolong QT interval with low TdP risk, likely because they block additional inward currents. We investigated the utility of J-T interval, a novel biomarker of inward current block and TdP risk, in conscious telemetered guinea pigs. Read More

View Article and Full-Text PDF

Discovery and preclinical profile of sudapyridine (WX-081), a novel anti-tuberculosis agent.

Bioorg Med Chem Lett 2022 Sep 27;71:128824. Epub 2022 May 27.

WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China. Electronic address:

Multidrug resistant tuberculosis (MDR-TB) remains a major human health challenge. Bedaquiline was approved in 2012 by the US FDA, and listed by WHO as a treatment for multidrug-resistant tuberculosis (MDR-TB) in 2018. However, the side effects of bedaquiline including the risk of unexplained mortality, QTc prolongation and hepatotoxicity limit its wide clinical use. Read More

View Article and Full-Text PDF
September 2022

Delayed Ventricular Repolarization and Sodium Channel Current Modification in a Mouse Model of Rett Syndrome.

Int J Mol Sci 2022 May 20;23(10). Epub 2022 May 20.

School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK.

Rett syndrome (RTT) is a severe developmental disorder that is strongly linked to mutations in the gene. RTT has been associated with sudden unexplained death and ECG QT interval prolongation. There are mixed reports regarding QT prolongation in mouse models of RTT, with some evidence that loss of function enhances cardiac late Na current, I. Read More

View Article and Full-Text PDF