Long QT syndrome: beyond making a diagnosis

Challenging Concepts in Congenital and Acquired Heart Disease in the Young ◽

10.1093/med/9780198759447.003.0014 ◽

2020 ◽

pp. 189-200

Author(s):

Gabrielle Norrish ◽

Juan Pablo Kaski

Keyword(s):

Long Qt Syndrome ◽

Ventricular Arrhythmias ◽

Beta Blockers ◽

Psychological Impact ◽

Population Screening ◽

Implantable Cardioverter Defibrillators ◽

Long Qt ◽

Arrhythmic Death ◽

Arrhythmic Event ◽

Qt Syndrome

Long QT syndrome (LQTS) is an uncommon, but important, cause of ventricular arrhythmias. The diagnosis is straightforward in symptomatic patients with marked QT prolongation on a resting 12-lead electrocardiogram (ECG). However, in many patients, the ECG findings are dynamic, and to make the diagnosis, clinicians need to be aware of suggestive features. The greatest challenge in managing these patients is risk stratification for a sudden arrhythmic event. Beta-blockers have been shown to reduce the risk for ventricular arrhythmias in all genotype-positive patients, regardless of 12-lead ECG findings. For patients in whom beta-blockers are contraindicated, left cardiac sympathetic denervation may be a useful therapy. Implantable cardioverter–defibrillators have a role to play in preventing sudden cardiac death, although their use should be balanced with associated complications and psychological impact. Population screening for LQTS remains controversial. Screening of first-degree relatives in sudden arrhythmic death syndrome is recommended, but population screening is not currently undertaken in the United Kingdom.

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Clinical presentation of Long QT Syndrome in a case series study in Iraq

Journal of the Faculty of Medicine Baghdad ◽

10.32007/jfacmedbagdad.6231753 ◽

2020 ◽

Vol 62 (3) ◽

Author(s):

AMAR Talib AL-HAMDI

Keyword(s):

Long Qt Syndrome ◽

Qt Interval ◽

Beta Blockers ◽

Case Series ◽

Long Qt ◽

Drug Induced ◽

Arrhythmic Death ◽

Case Series Study ◽

Qt Syndrome ◽

Series Study

Background: Long QT syndrome is an important cause of arrhythmic death, and it is characterized by electrocardiographic changes and a prolonged QT interval. Patients may present with sudden cardiac death, recurrent syncope, and palpitation.Objective: Clinical orientation for the Long QT syndrome and minimizing its misdiagnosis to achieve high diagnostic index.Patients and Methods: Patients presenting with ventricular arrhythmias, syncope, dizzy spells, and prolonged, non-drug-induced QT interval from 2004 uptil 2019 at Al Nasirya Heart Center , Al Sulaimanya Heart Hospital, and Al Nahrain Teaching Hospital were enrolled in this study. All aptients studied clinically and followed up. Management included beta blocker drug therapy and ICD implantation.Results: Forty-two patients were included within 15 years, comprising 22 pediatric and 20 adult patients (26 males, 16 females). Ventricular fibrillation reported in 18 patients and ventricular tachycardia in five patients. Thirty-eight patients received beta blockers, and 85% showed marked reduction in ventricular arrhythmia events. Implantable cardioverter-defibrillator (ICD) was implanted in 34 patients.The diagnosis of Long QT syndrome was missed in 85% of cases during the provisional medical contacts .Conclusion: In this case series study patients with LQTS presented with syncope, recurrent dizzy spells or palpitation. The diagnosis requires high index of diagnostic suspicion.This case study is intended to orient physicians to diagnosis this fatal problem.

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P6587The experience of a French specialized inherited arrhythmia center in the management of long QT syndrome patients

European Heart Journal ◽

10.1093/eurheartj/ehz746.1175 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

V Probst ◽

M Minier ◽

P Mabo ◽

G Clerici ◽

D Babuty ◽

...

Keyword(s):

Long Qt Syndrome ◽

Genetic Screening ◽

Ventricular Arrhythmias ◽

University Hospital ◽

Baseline Heart Rate ◽

Qtc Interval ◽

Long Qt ◽

Inherited Arrhythmia ◽

Arrhythmic Event ◽

Qt Syndrome

Abstract Introduction Congenital long QT syndrome (LQTS) is a hereditary disease characterized by prolonged QTc interval and risk of ventricular tachyarrhythmias, which may lead to syncope, cardiac arrest, or sudden death in young people. Objective The aim of this study is to report the experience of the French referral center of inherited arrhythmia of the University Hospital of Nantes. Methods Consecutive patients affected with lonq QT syndrome were recruited in a multicentric prospective registry in France (15 centers) between 1997 and 2018. Clinical data and 12-lead ECG were collected. Genetic screening was performed using dHPLC-DNA sequencing, HRM or targeted sequencing for at least KCNQ1, KCNH2 and SCN5A. Results In this study, we enrolled a total of 741 patients affected by LQTS according to the Schwartz score (447 (60%) females, 404 (55%) index cases). Mean age at diagnosis was 33±21 years. In this cohort, 343 patients (46%) were symptomatic: 66 patients experienced resuscitated sudden cardiac death (SCD, 9%), 211 (28%) syncope and 66 (9%) ventricular arrhythmias. One hundred and two patients (14%) had history of familial SCD. At baseline, heart rate was 69±19 bpm, PR 149±39 mm, QRS 86±16 mm and QTc 479±62 mm. Three hundred and eighty-six patients (52%) were treated with beta-blockers and 88 patients (12%) were implanted with an ICD. Genetic screening was performed in 668 (90%) patients. Genetic screening for the 3 major genes of LQTS was positive for 411 patients (62%): 165 variants (25%) in KCNQ1, 178 variants (27%) in KCNH2, 68 variants (10%) in SCN5A. Moreover, we found variants in minor genes of LQTS for 22 patients (3%). During a mean follow-up of 6.2±5.2 years, 64 patients (9%) underwent arrhythmic events (7 SCD (1%), 8 appropriate ICD therapy (1%) and 49 ventricular arrhythmias (7%). The rate of arrhythmic event was 1.39%/y. Mean age at the first event was 41.7±21.5 years. Sixteen patients (2%) died of non-arrhythmic causes. Conclusion Care in a specialized inherited arrhythmia center is associated with a low incidence of arrhythmic event (1.39%/y) in patients affected with LQTS.

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Faculty Opinions recommendation of Not all beta-blockers are equal in the management of long QT syndrome types 1 and 2: higher recurrence of events under metoprolol.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717968556.793468235 ◽

2012 ◽

Author(s):

Andrew Krahn ◽

Pradyot Saklani ◽

Manoj Obeyesekere

Keyword(s):

Long Qt Syndrome ◽

Beta Blockers ◽

Long Qt ◽

Qt Syndrome

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Fever-induced QTc prolongation and ventricular arrhythmias in individuals with type 2 congenital long QT syndrome

Journal of Clinical Investigation ◽

10.1172/jci35337 ◽

2008 ◽

Cited By ~ 5

Author(s):

Ahmad S. Amin ◽

Lucas J. Herfst ◽

Brian P. Delisle ◽

Christine A. Klemens ◽

Martin B. Rook ◽

...

Keyword(s):

Long Qt Syndrome ◽

Ventricular Arrhythmias ◽

Qtc Prolongation ◽

Long Qt ◽

Qt Syndrome ◽

Congenital Long Qt Syndrome

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The Electrophysiological Mechanism of Ventricular Arrhythmias in the Long QT Syndrome

Circulation Research ◽

10.1161/01.res.79.3.474 ◽

1996 ◽

Vol 79 (3) ◽

pp. 474-492 ◽

Cited By ~ 264

Author(s):

Nabil El-Sherif ◽

Edward B. Caref ◽

Hong Yin ◽

Mark Restivo

Keyword(s):

Long Qt Syndrome ◽

Ventricular Arrhythmias ◽

Long Qt ◽

Qt Syndrome ◽

Electrophysiological Mechanism

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ECG patterns related to arrhythmias and sudden death: channelopathies, early repolarization, and pre-excitation

ESC CardioMed ◽

10.1093/med/9780198784906.003.0074 ◽

2018 ◽

pp. 382-389

Author(s):

Wojciech Zareba ◽

Pyotr Platonov

Keyword(s):

Sudden Death ◽

Long Qt Syndrome ◽

Ventricular Arrhythmias ◽

Prior History ◽

Long Qt ◽

Early Repolarization ◽

Genes Encoding ◽

History Of ◽

Qt Syndrome ◽

Characteristic Features

Electrocardiogram (ECG) patterns recognized in patients with sudden death without structural abnormalities in the heart have guided cardiology over the last few decades towards a better understanding of the role of cardiac ion channels in physiology and in arrhythmogenicity in rare electrical diseases. The long QT syndrome became the paradigm for evaluating the association between specific ion channel abnormalities caused by mutations in genes encoding predominantly potassium and sodium channels and phenotypic ECG expression. Specific ECG patterns observed in long QT syndrome help in diagnosis and improve prognosis in patients affected by this disorder. Short QT syndrome also is characterized by specific patterns in repolarization morphology that relate to affected potassium current or calcium handling genes. Brugada syndrome and early repolarization syndrome are considered as J-wave syndromes, having some similarities in ECG features but with distinctive patterns associated with classical forms of these disorders. Spontaneous appearance of cove-type Brugada pattern is associated with a worse prognosis. Early repolarization patterns may also indicate prognosis in subjects with a prior history of cardiac arrest or ventricular arrhythmias or a family history of cardiac arrests. Catecholaminergic polymorphic ventricular tachycardia is another channelopathy without characteristic features in standard resting ECG but with characteristic polymorphic ventricular arrhythmias during catecholaminergic challenge (exercise test, stressing situations). Pre-excitation syndromes associated with sudden cardiac death are well recognized and current understanding of these disorders leads to a better therapy.

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The Efficacy of Beta-Blockers in Patients With Long QT Syndrome 1–3 According to Individuals’ Gender, Age, and QTc Intervals: A Network Meta-analysis

Frontiers in Pharmacology ◽

10.3389/fphar.2020.579525 ◽

2020 ◽

Vol 11 ◽

Author(s):

Lu Han ◽

Fuxiang Liu ◽

Qing Li ◽

Tao Qing ◽

Zhenyu Zhai ◽

...

Keyword(s):

Long Qt Syndrome ◽

Clinical Evidence ◽

Beta Blockers ◽

Meta Analysis ◽

Cardiac Events ◽

Long Qt ◽

Confounding Variables ◽

Qt Syndrome ◽

The Relationship

Long QT syndrome (LQTS) is an arrhythmic heart disease caused by congenital genetic mutations, and results in increased occurrence rates of polymorphic ventricular tachyarrhythmias and sudden cardiac death (SCD). Clinical evidence from numerous previous studies suggested that beta blockers (BBs), including atenolol, propranolol, metoprolol, and nadolol, exhibit different efficacies for reducing the risk of cardiac events (CEs), such as syncope, arrest cardiac arrest (ACA), and SCD, in patients with LQTS. In this study, we identified relevant studies in MEDLINE, PubMed, embase, and Cochrane databases and performed a meta-analysis to assess the relationship between the rate of CEs and LQTS individuals with confounding variables, including different gender, age, and QTc intervals. Moreover, a network meta-analysis was not only established to evaluate the effectiveness of different BBs, but also to provide the ranked efficacies of BBs treatment for preventing the recurrence of CEs in LQT1 and LQT2 patients. In conclusion, nadolol was recommended as a relatively effective strategy for LQT2 in order to improve the prognosis of patients during a long follow-up period.

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