Abstract 16509: Young Long QT Syndrome Patients With KCNH2 Mutations Have Late Onset but Severe Symptoms

Introduction: The long QT syndrome (LQTS) is one of the causes of sudden cardiac death in children. Although the risk factors for cardiac events depending on the genotype have been reported, age-related difference in phenotype remains unknown. Objectives: We aimed to clarify the age-and genotype-related clinical features in the young LQTS cohort (form 1 to 20y.o.). Methods and Results: This study comprised 101 symptomatic LQTS patients that were genotyped (male n=36, mean age 10.6±4.3). We excluded patients with multiple mutations. Fifty patients carried heterozygous mutations in KCNQ1, 48 in KCNH2 and 3 in SCN5A. LQTS-related cardiac events were classified into 3 categories; syncope, documented Torsades de pointes (TdP) and cardio-pulmonary arrest (CPA). Ninety patients experienced syncope, 7 were documented TdP and 4 suffered CPA. Figure shows a frequency histogram for the ages of first event in each genotype. The mean age of the onset in KCNH2 mutation carriers were significantly older (12.2±4.6y.o.) than those in KCNQ1 (9.2±3.5y.o., p<0.001). The numbers and mean ages of the patients suffered CPA were 1 in KCNQ1 (12y.o.), 2 in KCNH2 (10.5±3.5y.o.) and 1 in SCN5A (6y.o.). TdP was significantly more frequently documented in the patients with KCNH2 mutations (n=6, 13.7±3.3y.o.) than those with KCNQ1 mutations (n=1, 9y.o., p=0.029). Conclusion: In the young LQTS patients, therefore, KCNH2 mutation carriers showed a severer phenotype than those of KCNQ1, though their age of onset was older. These finding helped us to choose more appropriate preventive therapy depend on the age of onset and genotype.

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Abstract 2636: Age-Related Triggers for Life-Threatning Arrhythmia in the Genotyped Long QT Syndrome

Circulation ◽

10.1161/circ.116.suppl_16.ii_584-a ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Tomoko Sakaguchi ◽

Wataru Shimizu ◽

Hideki Ito ◽

Takashi Noda ◽

Yoshihiro Miyamoto ◽

...

Keyword(s):

Long Qt Syndrome ◽

Study Cohort ◽

List Type ◽

Age Group ◽

Cardiac Events ◽

Long Qt ◽

Age Related ◽

First Onset ◽

High Age ◽

Qt Syndrome

OBJECTIVES We aimed to examine whether triggers for cardiac events are different depending on the age in genotyped and symptomatic long QT syndrome (LQTS) patients. BACKGROUND Patients with LQTS become symptomatic in adolescence, but some at age ≥20 y/o. It remains unknown whether clinical features of these symptomatic LQTS patients differ depending on the onset of age. METHODS Study cohort consisted of consecutive 108 symptomatic LQTS patients (34 males and 74 females from 88 families) who were identified to carry the following genotypes; LQT1 (n = 48), LQT2 (n = 52), LQT3 (n = 8). They were divided into 2 groups according to the age of their first onset of symptoms (low age <20 y/o, n = 75, average age = 10 y/o, and high age ≥20 y/o, n = 33, average age = 43 y/o), and triggers of their cardiac events (ventricular tachycardia, syncope or cardiac arrest) were analyzed. We divided the triggers into 3 categories: adrenergically-mediated factors; exercise, emotional stress, loud noise and arousal, vagally-mediated factors; rest/sleep, and secondary factors; drugs, hypokalemia, and bradycardia. RESULTS Percentage of patients with family history was significantly higher in the low age group (68% vs. 39%; p = 0.005), and prevalence of females and probands were significantly higher in the high age group (60% vs. 88%; p = 0.004, 75% vs. 97%; p = 0.006, respectively). There were no significant differences in both QTc intervals (523 ± 7 ms vs. 505 ± 10; p = 0.15) and Schwartz scores (6.3 ± 0.2 vs. 5.6 ± 0.3; p = 0.06) between the 2 groups. In the low age group, 76% of the cardiac events were initiated by adrenergically-mediated factors, and 20% were vagally mediated, but none was triggered by secondary factors. In contrast, in the high age group, 48% of the cardiac events were triggered by secondary factors, 12% adrenergically-mediated, and 18% vagally-mediated factors. The prevalence of secondary factors were as follows; 0/75 [0%] in low age vs. 16/33 [48%] in high age; p < 0.001. About the subdivision of secondary triggers on the genotype, hypokalemia was only observed in LQT1, drugs mainly in LQT2, and bradycardia only in LQT2. CONCLUSION Arrhythmic triggers in LQTS differ depending on the age of the patients, stressing the importance of age-related therapy for genotyped LQTS patients.

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Inducible torsades de pointes during an acute face immersion test in an adolescent with type 2 long QT syndrome

Cardiology in the Young ◽

10.1017/s1047951120002176 ◽

2020 ◽

Vol 30 (8) ◽

pp. 1171-1172

Author(s):

Jun Muneuchi ◽

Yuichiro Sugitani ◽

Mamie Watanabe

Keyword(s):

Long Qt Syndrome ◽

Torsades De Pointes ◽

Immersion Test ◽

Cardiac Events ◽

Long Qt ◽

Face Immersion ◽

Qt Syndrome

AbstractWe present the case of a 12-year-old boy with type 2 long QT syndrome in whom torsades de pointes was induced by an acute face immersion test. This test is feasible to predict cardiac events in adolescents with long QT syndrome.

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Management of Long QT Syndrome in Women Before, During, and After Pregnancy

US Cardiology Review ◽

10.15420/usc.2021.02 ◽

2021 ◽

Vol 15 ◽

Author(s):

Caroline Taylor ◽

Bruce S Stambler

Keyword(s):

Long Qt Syndrome ◽

Postpartum Period ◽

Torsades De Pointes ◽

Close Monitoring ◽

Cardiac Events ◽

Long Qt ◽

Life Threatening ◽

Β Blocker ◽

Qt Syndrome ◽

Congenital Long Qt Syndrome

Congenital long QT syndrome (LQTS) is a primary genetic and electrical disorder that increases risk for torsades de pointes, syncope, and sudden death. Post-pubertal women with LQTS require specialized multidisciplinary management before, during, and after pregnancy involving cardiology and obstetrics to reduce risk for cardiac events in themselves and their fetuses and babies. The risk of potentially life-threatening events is lower during pregnancy but increases significantly during the 9-month postpartum period. Treatment of women with LQTS with a preferred β-blocker at optimal doses along with close monitoring are indicated throughout pregnancy and during the high-risk postpartum period.

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Pediatric Cohort With Long QT Syndrome　– KCNH2 Mutation Carriers Present Late Onset But Severe Symptoms –

Circulation Journal ◽

10.1253/circj.cj-15-0933 ◽

2016 ◽

Vol 80 (3) ◽

pp. 696-702 ◽

Cited By ~ 8

Author(s):

Junichi Ozawa ◽

Seiko Ohno ◽

Takashi Hisamatsu ◽

Hideki Itoh ◽

Takeru Makiyama ◽

...

Keyword(s):

Long Qt Syndrome ◽

Late Onset ◽

Long Qt ◽

Mutation Carriers ◽

Qt Syndrome

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Congenital Long QT Syndrome in an Infant

Acta Chirurgica Latviensis ◽

10.2478/v10163-010-0023-4 ◽

2009 ◽

Vol 9 (1) ◽

pp. 111-112

Author(s):

Aris Lacis ◽

Inga Lace ◽

Elina Teivane ◽

Vita Knauere ◽

Inguna Lubaua ◽

...

Keyword(s):

Sudden Death ◽

Long Qt Syndrome ◽

Heart Rhythm ◽

Torsades De Pointes ◽

Cardiac Events ◽

Long Qt ◽

Heart Rhythm Disorders ◽

Qt Syndrome ◽

First Year Of Life ◽

Congenital Long Qt Syndrome

Congenital Long QT Syndrome in an InfantLong QT syndrome (LQTS) is a disorder of myocardial repolarization characterized by prolonged QT interval on ECG with prevalence close to 1/3000-1/5000. LQTS is characterized by the occurrence of syncopal episodes due to torsades de pointes ventricular tachycardia (VT) and by a high risk for sudden cardiac death among untreated patients (1, 2, 3). In 12% of patients with LQTS, sudden death is the first manifestation of the disease and only in 4% this happens in the first year of life (2). There is consensus that all symptomatic children with LQTS should be treated with β-blockers which are effective in preventing cardiac events and reducing mortality in 70%, but do not protect patients from sudden death completely (1,2,3,4). The prognosis is poor in untreated patients with annual mortality 20% and 10 year mortality up to 50% (1, 2). Here we present a case of relatively rare congenital heart rhythm disorders in an infant which required immediate treatment.

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Faculty Opinions recommendation of Risk of life-threatening cardiac events among patients with long QT syndrome and multiple mutations.

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

10.3410/f.717984108.793473300 ◽

2013 ◽

Author(s):

Robert Sheldon ◽

Tarek Hatoum

Keyword(s):

Long Qt Syndrome ◽

Cardiac Events ◽

Long Qt ◽

Life Threatening ◽

Qt Syndrome

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A rare indication of permanent pacemaker implantation in children: congenital long QT syndrome

Cardiology in the Young ◽

10.1017/s1047951120003108 ◽

2020 ◽

Vol 30 (12) ◽

pp. 1880-1881

Author(s):

Mehmet Taşar ◽

Nur Dikmen Yaman ◽

Huseyin Dursin ◽

Murat Şimşek ◽

Senem Özgür

Keyword(s):

Sudden Death ◽

Long Qt Syndrome ◽

Pacemaker Implantation ◽

Torsades De Pointes ◽

Permanent Pacemaker ◽

Long Qt ◽

Permanent Pacemaker Implantation ◽

Qt Syndrome ◽

Congenital Lqts ◽

Congenital Long Qt Syndrome

AbstractCongenital Long QT Syndrome (LQTS) is a dangerous arrhythmic disorder that can be diagnosed in children with bradycardia. It is characterised by a prolonged QT interval and torsades de pointes that may cause sudden death. Long QT syndrome is an ion channelopathy with complex molecular and physiological infrastructure. Unlike the acquired type, congenital LQTS has a genetic inheritance and it may be diagnosed by syncope, stress in activity, cardiac dysfunction, sudden death or sometimes incidentally. Permanent pacemaker implantation is required for LQTS with resistant bradycardia even in children to resolve symptoms and avoid sudden death.

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