Clinical presentation and course of long QT syndrome in Thai children

Saprungruang, Ankavipar; Vithessonthi, Kanyalak; La-orkhun, Vidhavas; Lertsapcharoen, Pornthep; Khongphatthanayothin, Apichai

doi:10.1016/j.joa.2015.03.009

Cited by 5 publications

(4 citation statements)

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“…There were reports on various gene mutation frequency in Asian countries [ [7] , [8] , [9] , [10] , [11] , [12] ]. From a previous study in Thai children, the ratio of LQTS patients who had cardiac events at rest or sleep appeared to be higher than those found in other Asian countries [ 13 ]. However, genetic testing results was not previously examined in Thai population.…”

Section: Introductionmentioning

confidence: 95%

Genotype and clinical characteristics of congenital long QT syndrome in Thailand

Saprungruang

Khongphatthanayothin

Mauleekoonphairoj

et al. 2018

Indian Pacing and Electrophysiology Journal

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BackgroundCongenital long QT syndrome (LQTS) is an inheritable arrhythmic disorder which is linked to at least 17 genes. The clinical characteristics and genetic mutations may be variable among different population groups and they have not yet been studied in Thai population.MethodsClinical characteristics were retrospectively reviewed from children and young adults with congenital long QT syndrome whose blood samples were sent for genotyping during 1998–2017. Sangers sequencing was used to sequentially identify KCNQ1 or KCNH2 genetic variants. Whole exome sequencing (WES) was used to identify variants in all other known LQTS genes.ResultsOf the 20 subjects (17 families), 45% were male, mean QTc was 550.3 ± 68.8 msec (range 470–731 msec) and total Schwartz's score was 5.6 ± 1.2 points (range 3–8 points). Fifty percent of patients had events at rest, 30% had symptoms after adrenergic mediated events, and 20% were asymptomatic. We discovered pathogenic and likely pathogenic genetic variants in KCNQ1, KCNH2, and SCN5A in 6 (35%), 4 (24%), and 2 (12%) families, respectively. One additional patient had variance of unknown significance (VUS) in KCNH2 and another one in ANK2. No pathogenic genetic variant was found in 3 patients (18%). Most patients received beta-blocker and 9 (45%) had ICD implanted. LQT1 patients were either asymptomatic or had stress-induced arrhythmia. Most of the LQT2 and LQT3 patients developed symptoms at rest or during sleep.ConclusionsOur patients with LQTS were mostly symptomatic at presentation. The genetic mutations were predominantly in LQT1, LQT2, and LQT3 genes.

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Section: Introductionmentioning

confidence: 95%

Genotype and clinical characteristics of congenital long QT syndrome in Thailand

Saprungruang

Khongphatthanayothin

Mauleekoonphairoj

et al. 2018

Indian Pacing and Electrophysiology Journal

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“…Beta-blocker is recognized as the efficacious mainstay of therapy for LQT1 and LQT2. Atenolol is a common beta-blocker used in children in the Asia-Pacific region, in contrast to other parts of the world [12] . In Australia, atenolol has been used as the first-line choice of beta-blocker for children and adolescents with LQTS due to its availability.…”

Section: Discussionmentioning

confidence: 99%

Ten‐year experience in atenolol use and exercise evaluation in children with genetically proven long QT syndrome

Kwok

Pflaumer

Pantaleo

et al. 2017

Journal of Arrhythmia

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BackgroundDue to its availability, atenolol is the primary beta-blocker used in Australia for children with long QT syndrome. There is limited data on long-term follow-up of its use.MethodsA single-tertiary-center, retrospective, observational study investigating all children and adolescents who had genetically proven long QT syndrome type 1 (LQT1) and type 2 (LQT2) was conducted. Their pretreatment exercise tests were evaluated for QTc intervals into the recovery phase of exercise.ResultsEighty six patients were identified (LQT1, 67, and LQT2, 19) from 2004 to 2014. The majority (86%) of patients were initially referred for family screening. Atenolol was administered at a mean dose of 1.58 ± 0.51 mg/kg/day. During the median follow-up period of 4.29 years, only one proband developed ventricular arrhythmia whilst taking atenolol, No patient had cardiac arrest or aborted cardiac arrest. With respect to side effects of atenolol, only two patients had intolerable side effects necessitating changes of medication. Evaluation of exercise tests (pretreatment) demonstrated that corrected QT (QTc) intervals at 2–3 min into the recovery phase of exercise were significantly prolonged for LQT1 patients. LQT1 patients with transmembrane mutation had longer QTc intervals than their C-terminus mutation counterparts, reaching statistical significance at 3 min into the recovery phase of exercise.ConclusionsAtenolol is an effective treatment for genetically proven LQT1 and LQT2 children and adolescents, with good tolerability. In LQT1 patients, QTc intervals at 2–3 min into the recovery phase of exercise were significantly prolonged, particularly in patients with transmembrane mutations.

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“…Voltage-gated potassium (K v ) channels are known for their relation to malignant cardiac arrhythmias, where blocked or nonfunctional K v channels cause long QT syndrome (LQTS) because of impaired cardiac repolarization.1 Patients with this syndrome have a susceptibility for cardiac arrest and sudden death secondary to the development of polymorphic ventricular tachycardia or torsades de pointes. 1 Long-QT syndrome can either be acquired or congenital. Although the association between acquired LQTS and medications, electrolyte abnormalities, and endocrinopathies have been widely recognized, congenital LQTS is a relatively rare channelopathy with an incidence of 1/2,500.…”

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confidence: 99%

“…2 It is classified numerically as LQT1 to LQT13 according to various sites of mutation in the gene loci. 1,2 Voltage-gated potassium channels also play a role in glucagon and insulin secretion from the pancreatic α and β cells, which are crucial for glucose regulation. 3 We describe a patient found to have a prolonged QTc in the setting of newly diagnosed Type 1 diabetes mellitus (DM).…”

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Congenital long-QT syndrome in type 1 diabetes: a unique association

et al. 2019

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Kurnaz E, Savaş Erdeve Ş, Özgür S, Keskin M, Özbudak P, Çetinkaya S, Aycan Z. Congenital long-QT syndrome in type 1 diabetes: a unique association. Turk J Pediatr 2019; 61: 791-793.In contrast to acquired long QT syndrome (LQTS), congenital LQTS is a relatively rare channelopathy with an incidence of 1/2,500. We describe a patient found to have a prolonged QTc in the setting of newly diagnosed Type 1 DM. To the best of our knowledge, this unique association has not been previously reported. Currently, it is shown that glucose ingestion aggravated cardiac repolarization disturbances in LQT2 patients and prolonged the cardiac repolarization phase in healthy controls. Our case presented to the hospital with syncope after increased glucose level. Therefore, it seems that increased glucose level may have prolonged QTc interval and aggravated cardiac repolarization disturbances in the presented case. By this report, we want to emphasize the importance of hyperglycaemia in congenital LQTS.

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Clinical presentation and course of long QT syndrome in Thai children

Abstract: All 20 patients with LQTS were mostly symptomatic at presentation. Owing to the geographical region and ethnicity of the Thai population, we conclude that the ratio of patients who develop cardiac symptoms at rest or during sleep might be higher than in other Asian countries.

Cited by 5 publications

References 12 publications

Genotype and clinical characteristics of congenital long QT syndrome in Thailand

Genotype and clinical characteristics of congenital long QT syndrome in Thailand

Ten‐year experience in atenolol use and exercise evaluation in children with genetically proven long QT syndrome

Congenital long-QT syndrome in type 1 diabetes: a unique association

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