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Lqts review

Adaya Weissler-Snir, Michael H Gollob, Vijay Chauhan, Melanie Care, Danna A Spears
BACKGROUND: In about 20-25% of patients with congenital long QT syndrome (LQTS) a causative pathogenic mutation is not found. The aim of this study was to explore the prevalence of alternative cardiac diagnoses among patients exhibiting prolongation of QT interval with negative genetic testing for LQTS genes. METHODS: We conducted a retrospective analysis of 239 consecutive patients who were evaluated in the inherited arrhythmia clinic at the Toronto General Hospital between July 2013 and December 2015 for possible LQTS...
February 3, 2017: Pacing and Clinical Electrophysiology: PACE
Kamalan Jeevaratnam, Karan R Chadda, Samantha C Salvage, Haseeb Valli, Shiraz Ahmad, Andrew A Grace, Christopher L-H Huang
Ageing is associated with increased prevalences of both atrial and ventricular arrhythmias, reflecting disruption of the normal sequence of ion channel activation and inactivation generating the propagated cardiac action potential. Experimental models with specific ion channel genetic modifications have helped clarify the interacting functional roles of ion channels and how their dysregulation contributes to arrhythmogenic processes at the cellular and systems level. They have also investigated interactions between these ion channel abnormalities and age-related processes in producing arrhythmic tendency...
December 26, 2016: Clinical and Experimental Pharmacology & Physiology
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
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...
December 2016: Herzschrittmachertherapie & Elektrophysiologie
Jennifer L Smith, Corey L Anderson, Don E Burgess, Claude S Elayi, Craig T January, Brian P Delisle
The molecular mechanisms underlying congenital long QT syndrome (LQTS) are now beginning to be understood. New insights into the etiology and therapeutic strategies are emerging from heterologous expression studies of LQTS-linked mutant proteins, as well as inducible pluripotent stem cell derived cardiomyocytes (iPSC-CMs) from LQTS patients. This review focuses on the major molecular mechanism that underlies LQTS type 2 (LQT2). LQT2 is caused by loss of function (LOF) mutations in KCNH2 (also known as the human Ether-à-go-go-Related Gene or hERG)...
October 2016: Journal of Arrhythmia
Kafa Walweel, Ye Win Oo, Derek R Laver
Cardiac output and rhythm depend on the release and the take-up of calcium from the sarcoplasmic reticulum (SR). Excessive diastolic calcium leak from the SR due to dysfunctional calcium release channels (RyR2) contributes to the formation of delayed after-depolarizations, which underlie the fatal arrhythmias that occur in heart failure and inherited syndromes. Calmodulin (CaM) is a calcium-binding protein that regulates target proteins and acts as a calcium sensor. CaM is comprised of two calcium-binding EF-hand domains and a flexible linker...
January 2017: Clinical and Experimental Pharmacology & Physiology
Bettina F Cuneo, Janette F Strasburger, Ronald T Wakai
INTRODUCTION: Fetal magnetocardiography (fMCG), the magnetic analog of ECG, has provided invaluable insight into the mechanisms of fetal arrhythmias. In the past 15years, we have evaluated over 300 fetuses with arrhythmia by fMCG. We review the unique characteristics and natural history of the long QT syndrome (LQTS) rhythms. METHODS: We reviewed the fMCGs of subjects referred with suspected LQTS based on either a positive family history or echo diagnosis of the LQTS rhythms (sinus bradycardia, ventricular tachycardia, or 2:1 AV conduction) to the Biomagnetism laboratory in the Department of Medical Physics, UW-Madison...
November 2016: Journal of Electrocardiology
Kathryn E Waddell-Smith, Jian Li, Warren Smith, Jackie Crawford, Jonathan R Skinner
BACKGROUND: Long-term uninterrupted β-blockade significantly reduces cardiac events in long QT syndrome (LQTS). Despite this, data on nonadherence are scarce and quantified only on the day of cardiac arrest in LQTS literature. We aimed to describe β-blocker adherence, and predictors thereof, among patients with LQTS types 1 and 2. METHODS AND RESULTS: Electronic health records and pharmacy dispensing data were reviewed for 90 patients with LQTS 1 and 2 who reside in Auckland, New Zealand, during a 34-month period...
August 2016: Circulation. Arrhythmia and Electrophysiology
Aarti Dalal, Richard J Czosek, Joshua Kovach, Johannes C von Alvensleben, Santiago Valdes, Susan P Etheridge, Michael J Ackerman, Debbie Auld, Jeryl Huckaby, Courtney McCracken, Robert Campbell
OBJECTIVES: To identify the clinical presentation of children and adolescents affected by 1 of 4 cardiac conditions predisposing to sudden cardiac arrest: hypertrophic cardiomyopathy, long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and anomalous origin of the left coronary artery from the right sinus of Valsalva (ALCA-R). STUDY DESIGN: This was a retrospective review of newly diagnosed pediatric patients with hypertrophic cardiomyopathy, LQTS, CPVT, and ALCA-R referred for cardiac evaluation at 6 US centers from 2008 to 2014...
October 2016: Journal of Pediatrics
Andrew P Landstrom, Nicole J Boczek, Dan Ye, Christina Y Miyake, Caridad M De la Uz, Hugh D Allen, Michael J Ackerman, Jeffrey J Kim
BACKGROUND: Mutations in the CACNA1C-encoded L-type calcium channel have been associated with Timothy syndrome (TS) with severe QT prolongation, syndactyly, facial dysmorphisms, developmental delay, and sudden death. Recently, patients hosting CACNA1C mutations with only long QT syndrome (LQTS) have been described. We sought to identify novel variants in CACNA1C associated with either TS or LQTS, and to determine the impact of the mutation on channel function. METHODS/RESULTS: Two probands were identified with mutations in CACNA1C, one with a TS-associated mutation, G406R, and a second with genotype-negative LQTS...
October 1, 2016: International Journal of Cardiology
Alessandro Faragli, Katherine Underwood, Silvia G Priori, Andrea Mazzanti
The identification of patients at risk for sudden cardiac death (SCD) is fundamental for both acquired cardiovascular diseases (such as coronary artery diseases, CAD) and inherited arrhythmia syndromes (such as the long-QT syndrome, LQTS). Genetics may play a role in both situations, although the potential to exploit this information to reduce the burden of SCD varies among these two groups. Concerning acquired cardiovascular diseases, which affect most of the general population, preliminary data suggest an association between genetics and the risk of dying suddenly...
September 2016: Journal of Cardiovascular Electrophysiology
Matthew L Furst, Peter F Aziz
Congenital Long QT Syndrome (LQTS) results in abnormal ventricular repolarization in patients with otherwise structurally normal hearts. Following the initial clinical descriptions of LQTS, there has been a great deal of investigation into the genetic etiology and pathophysiology of these entities, with the goal of improved screening tools and understanding of associated risks. Through this work, heart rhythm experts continue to revise their recommendations regarding sports eligibility. We review the evolution of sports participation recommendations for LQTS...
May 9, 2016: Trends in Cardiovascular Medicine
C N Lang, G Koren, K E Odening
Long QT syndrome (LQTS) is a rare inherited channelopathy caused mainly by different mutations in genes encoding for cardiac K(+) or Na(+) channels, but can also be caused by commonly used ion-channel-blocking and QT-prolonging drugs, thus affecting a much larger population. To develop novel diagnostic and therapeutic strategies to improve the clinical management of these patients, a thorough understanding of the pathophysiological mechanisms of arrhythmogenesis and potential pharmacological targets is needed...
July 2016: Progress in Biophysics and Molecular Biology
Christopher C Cheung, Zachary W M Laksman, Gregory Mellor, Shubhayan Sanatani, Andrew D Krahn
Sudden cardiac death (SCD) in an apparently healthy individual is a tragedy that prompts a series of investigations to identify the cause of death and to prevent SCD in potentially at-risk family members. Several inherited channelopathies and cardiomyopathies, including long QT syndrome (LQTS), catecholaminergic polymorphic ventricular cardiomyopathy (CPVT), hypertrophic cardiomyopathy (HCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) are associated with exercise-related SCD. Exercise restriction has been a historical mainstay of therapy for these conditions...
April 2016: Canadian Journal of Cardiology
Matthew Hammond-Haley, Riyaz S Patel, Rui Providência, Pier D Lambiase
Inherited primary arrhythmia syndromes are a clinically heterogeneous group of relatively uncommon but important inherited cardiac conditions that are associated with an increased risk of sudden cardiac death (SCD) in the setting of a structurally normal heart. These include long-QT syndrome (LQTS), Short-QT syndrome (SQTS), Brugada syndrome (BrS) and Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT). The cardiomyopathies represent the other major group of inherited cardiac conditions associated with SCD, of which hypertrophic cardiomyopathy (HCM) is the most common...
April 15, 2016: International Journal of Cardiology
Colin H Peters, Mena Abdelsayed, Peter C Ruben
Cardiac arrhythmias are a prevalent cause of morbidity and mortality. In many cases, inheritable mutations in the genes encoding cardiac ion channels are the underlying cause of arrhythmias. Relative to other arrhythmogenic disorders, Brugada syndrome (BrS) is recently identified and not well-understood. Although most often referred to as a disease of cardiac sodium channels, familial BrS is now associated with 9 different genes. Of these genes, 4 alter sodium currents, and the most common known genetic cause remains loss-of-function mutants in the cardiac sodium channel gene SCN5A...
January 2016: Progress in Biophysics and Molecular Biology
Guoliang Li, Shuting Ma, Chaofeng Sun
Inherited long QT syndrome (LQTS) is an electrical heart disorder that manifests with syncope, seizures, and increased risk of torsades de pointes and sudden cardiac death. Dominant-negative current suppression is a mechanism by which pathogenic proteins disrupt the function of ion channels in inherited LQTS. However, current approaches for the management of inherited LQTS are inadequate. RNA interference (RNAi) is a powerful technique that is able to suppress or silence the expression of mutant genes. RNAi may be harnessed to knock out mRNAs that code for toxic proteins, and has been increasingly recognized as a potential therapeutic intervention for a range of conditions...
August 2015: Experimental and Therapeutic Medicine
Xiang-Lin Yang, Guo-Zhen Liu, Yun-Hai Tong, Hong Yan, Zhi Xu, Qi Chen, Xiang Liu, Hong-Hao Zhang, Hong-Bo Wang, Shao-Hua Tan
The electrocardiogram (ECG) has broad applications in clinical diagnosis and prognosis of cardiovascular disease. Many researchers have contributed to its progressive development. To commemorate those pioneers, and to better study and promote the use of ECG, we reviewed and present here a systematic introduction about the history, hotspots, and trends of ECG. In the historical part, information including the invention, improvement, and extensive applications of ECG, such as in long QT syndrome (LQTS), angina, and myocardial infarction (MI), are chronologically presented...
July 2015: Journal of Geriatric Cardiology: JGC
Peter F Aziz, Tammy Sweeten, Ramon L Vogel, William J Bonney, Jacqueline Henderson, Akash R Patel, Maully J Shah
OBJECTIVE: The study sought to examine the prevalence and outcomes of sports participation (both competitive and recreational) in our single-center LQTS genotype positive pediatric population. BACKGROUND: The risks of sports participation in patients with long QT syndrome (LQTS) are not clearly elucidated. METHODS: A retrospective review was performed on genotype positive patients referred for the evaluation and management of LQTS between 1998 and 2013 at the Children's Hospital of Philadelphia...
March 2015: JACC. Clinical Electrophysiology
Fernando Matias Gonzalez, Maria Assunta Veneziano, Anna Puggina, Stefania Boccia
BACKGROUND: Recent improvements in the identification of the genetic basis of long QT syndrome (LQTS) have led to significant changes in the diagnosis and management of this life-threatening condition. Genetic and electrocardiogram (ECG) tests are the most relevant examples among testing strategies for LQTS, yet their cost-effectiveness remains controversial. OBJECTIVE: The aim of this work was to review the available evidence on the cost-effectiveness of genetic and ECG testing strategies for the diagnosis of LQTS...
July 2015: Value in Health: the Journal of the International Society for Pharmacoeconomics and Outcomes Research
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