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CMAJ : Canadian Medical Association... Aug 2011
Topics: Adrenergic beta-Antagonists; Adult; British Columbia; Child, Preschool; Electrocardiography; Female; Humans; KCNQ1 Potassium Channel; Long QT Syndrome; Mutation; Prognosis
PubMed: 21482651
DOI: 10.1503/cmaj.100138 -
Pediatrics in Review Jul 1998The LQTS is no longer the rare "zebra" whose purpose is to ensure that trainees recall that deafness and sudden cardiac death may be related (Jervell and Lange-Nielsen... (Review)
Review
The LQTS is no longer the rare "zebra" whose purpose is to ensure that trainees recall that deafness and sudden cardiac death may be related (Jervell and Lange-Nielsen syndrome). Over the past 10 to 20 years, the number of cases of inherited LQTS (Romano-Ward syndrome) has increased dramatically. It is doubtful that this reflects a true increase in incidence of disease due to a greater rate of sporadic gene mutations occurring in the heart or because of a rising incidence of consanguinity. Rather, the "incidence" of LQTS has risen because of the emerging awareness of and respect for this electrical malady in the heart. Understanding the principal elements of the LQTS, knowing the types of presentations, and being able to identify its presence electrocardiographically will allow the astute physician to expose this silent killer.
Topics: Adolescent; Child; Child, Preschool; Diagnosis, Differential; Disease-Free Survival; Electric Countershock; Electrocardiography; Fatal Outcome; Female; Follow-Up Studies; Humans; Infant; Long QT Syndrome; Male
PubMed: 9654946
DOI: 10.1542/pir.19-7-232 -
Circulation Dec 2020
Topics: Arrhythmias, Cardiac; Humans; Long QT Syndrome
PubMed: 33347325
DOI: 10.1161/CIRCULATIONAHA.120.051434 -
Heart, Lung & Circulation 2007The long QT syndrome (LQTS) is a genetically transmitted cardiac arrhythmia due to ion channel protein abnormalities, which affects the transport of potassium and sodium... (Review)
Review
The long QT syndrome (LQTS) is a genetically transmitted cardiac arrhythmia due to ion channel protein abnormalities, which affects the transport of potassium and sodium ions across the cell membrane. Patients with LQTS may present with syncope, seizures or aborted cardiac arrest. LQTS is also an important cause of unexplained sudden cardiac death in the young. The diagnosis of LQTS is generally made on an ECG showing the prolonged QT interval. The establishment of LQTS registry and the discovery of genetic mutations causing LQTS have contributed greatly to the understanding of this condition and have also provided an impetus in understanding of other inherited cardiac arrhythmias. Genotype-phenotype correlation studies have allowed risk stratification of LQTS patients. Life style modification to avoid triggers for malignant cardiac arrhythmias, and the use of beta-blockers, pacemakers and implantable defibrillators, help to treat symptoms and reduce mortality in these patients.
Topics: Adrenergic beta-Antagonists; Cell Membrane; Death, Sudden, Cardiac; Genotype; Humans; Ion Channels; Long QT Syndrome; Mutation; Phenotype; Potassium; Prognosis; Risk Assessment; Risk Factors; Sodium
PubMed: 17627884
DOI: 10.1016/j.hlc.2007.05.008 -
Circulation Journal : Official Journal... 2014Congenital long QT syndrome (LQTS) is an inherited arrhythmia syndrome characterized by a prolonged QT interval on the 12-lead ECG, torsades de pointes and a higher... (Review)
Review
Congenital long QT syndrome (LQTS) is an inherited arrhythmia syndrome characterized by a prolonged QT interval on the 12-lead ECG, torsades de pointes and a higher chance of sudden cardiac death. LQTS segregates in a Mendelian fashion, which includes Romano-Ward syndrome with an autosomal dominant pattern as well as a rare autosomal recessive pattern (Jervell and Lange-Nielsen syndrome). Since 1957 when Jervell and Lange-Nielsen reported the first familial LQTS with congenital deafness, progress in understanding the genetic and electrophysiological mechanisms of LQTS has tremendously improved diagnostic methods and treatments. In the meantime, it has become evident that LQTS may not always be explained by a single gene mutation, but seems to follow a more complex genetic model intertwined with genetic common polymorphisms that have a mild to moderate effect on disease expression. In this review, we summarize the characteristics of LQTS (mainly LQT1-3) and briefly describe the most recent advances in LQTS clinical diagnostics as well as genetics.
Topics: Adrenergic beta-Antagonists; Autonomic Denervation; Combined Modality Therapy; Death, Sudden, Cardiac; Defibrillators, Implantable; Electrocardiography; Genes, Dominant; Genes, Recessive; Genetic Heterogeneity; Genotype; Humans; Ion Channels; Long QT Syndrome; Multifactorial Inheritance; Phenotype; Potassium; Romano-Ward Syndrome; Syncope
PubMed: 25274057
DOI: 10.1253/circj.cj-14-0905 -
The Journal of the Association of... Apr 2007Congenital Long QT Syndrome (cLQTS) is an inherited disease in children and adolescents who have structurally normal hearts but present with sudden death in a high... (Review)
Review
Congenital Long QT Syndrome (cLQTS) is an inherited disease in children and adolescents who have structurally normal hearts but present with sudden death in a high proportion of untreated patients. More than 300 mutations have been identified in 7 LQT genes. Diagnosis still depends on ECG, clinical presentations and family history. Molecular genetic testing is useful to unravel borderline family members of LQT probands, but it continues to be a research tool at present. Beta blockers remain the mainstay of treatment. ICDs are highly effective in reducing SCD for high risk patients. Gene based therapy is still preliminary. Considerable thought is needed to address and treat the asymptomatic LQT family members. The main cause of Acquired LQTS is inhibition of Ikr current, usually by drugs. Care must be taken to avoid further exposure to QT prolonging drugs or conditions. Physicians need to be aware of the pharmacodynamic and pharmacokinetic interactions of various important drugs.
Topics: Adolescent; Adrenergic beta-Antagonists; Cardiac Pacing, Artificial; Child, Preschool; Death, Sudden, Cardiac; Defibrillators, Implantable; Drug Interactions; Electrocardiography; Genetic Therapy; Humans; Life Style; Long QT Syndrome; Mutation; Prognosis; Risk; Sympathectomy
PubMed: 18368869
DOI: No ID Found -
Current Opinion in Pediatrics Oct 2009Advances in understanding the biophysical underpinnings of long QT syndrome have provided growing insight into the risk of this syndrome in the pediatric population.... (Review)
Review
PURPOSE OF REVIEW
Advances in understanding the biophysical underpinnings of long QT syndrome have provided growing insight into the risk of this syndrome in the pediatric population. This review focuses on developments in this area as reflected in the recent literature.
RECENT FINDINGS
QT interval prolongation on the surface ECG is the hallmark of long QT syndrome. This prolongation reflects protracted ventricular repolarization, primarily due to mutations in genes coding for cardiac ion channels. To date, 12 different genes have been implicated, and current genetic testing methods can provide a specific diagnosis in approximately 70% of patients. Clinical indicators, including age, sex, corrected QT duration, and prior syncope are the most powerful predictors of future life-threatening cardiac events. However, diagnosis, risk assessment, and therapeutic strategies are being guided by genetic analysis to an increasing degree.
SUMMARY
Impressive advancements have been made in understanding the genetic and clinical determinants of this heterogeneous syndrome. As genetic testing techniques become more robust, the ability to assess risk in affected individuals and tailor therapy will improve.
Topics: Adolescent; Age Factors; Child; Child, Preschool; Electrocardiography; Genotype; Humans; Infant; Long QT Syndrome; Phenotype; Risk Factors; Sex Factors; Young Adult
PubMed: 19617828
DOI: 10.1097/MOP.0b013e3283307ae2 -
BMJ (Clinical Research Ed.) Jan 2010
Topics: Adolescent; Diagnostic Errors; Electrocardiography; Female; Humans; Long QT Syndrome; Syncope
PubMed: 20061357
DOI: 10.1136/bmj.b4815 -
Current Problems in Cardiology Jun 1997
Review
Topics: Adrenergic beta-Antagonists; Anti-Arrhythmia Agents; Death, Sudden, Cardiac; Defibrillators, Implantable; Echocardiography; Electrocardiography; Humans; Long QT Syndrome; Prognosis; Survival Rate; Sympathectomy
PubMed: 9189673
DOI: 10.1016/s0146-2806(97)80009-6 -
Mayo Clinic Proceedings Mar 1998Once limited to discussions of the Jervell and Lange-Nielsen syndrome and Romano-Ward syndrome, the long QT syndrome (LQTS) is now understood to be a collection of... (Review)
Review
Once limited to discussions of the Jervell and Lange-Nielsen syndrome and Romano-Ward syndrome, the long QT syndrome (LQTS) is now understood to be a collection of genetically distinct arrhythmogenic cardiovascular disorders resulting from mutations in fundamental cardiac ion channels that orchestrate the action potential of the human heart. Our understanding of this genetic "channelopathy" has increased dramatically from electrocardiographic depictions of marked QT interval prolongation and torsades de pointes and clinical descriptions of people experiencing syncope and sudden death to molecular revelations in the 1990s of perturbed ion channel genes. More than 35 mutations in four cardiac ion channel genes--KVLQT1 (voltage-gated K channel gene causing one of the autosomal dominant forms of LQTS) (LQT1), HERG (human ether-a-go-go related gene.) (LQT2), SCN5A (LQT3), and KCNE1 (minK, LQT5)--have been identified in LQTS. These genes encode ion channels responsible for three of the fundamental ionic currents in the cardiac action potential. These exciting molecular break-throughs have provided new opportunities for translational research with investigations into genotype-phenotype correlations and gene-targeted therapies.
Topics: Anti-Arrhythmia Agents; Electrocardiography; Genotype; Humans; Ion Channels; Long QT Syndrome; Phenotype
PubMed: 9511785
DOI: 10.4065/73.3.250