Clinical features and follow-up of congenital long QT syndrome in children with syncope as the first presentation / 中国小儿急救医学

ABSTRACT

Objective:To investigate the pathogenic genes, clinical features and treatment as well as follow-up of children with congenital long QT syndrome (LQTS).Methods:The clinical data, genetic test results and follow-up data of 16 congenital LQTS children with syncope as the first manifestation admitted to the Department of Cardiology, Beijing Children′s Hospital Affiliated to Capital Medical University from August 2016 to March 2023 were collected and retrospectively analyzed.Results:Among the 16 LQTS patients, the age of first syncope onset was 1.3-13.3 (7.37±3.41) years, and the interval between first syncope onset and clinical diagnosis was 0-48 (14.8±16.2) months.A total of 13 (81.3%) patients had triggers of syncope, of which nine were exercise-induced and four were emotional induced.Genetic testing was performed in 13 patients with LQTS, of which 12 (92.3%) were found to have pathogenic or suspected pathogenic mutations from KCNQ1, KCNH2, and SCN5A gene.The corrected QT interval of 16 patients was (550.0±50.2) ms, all cases≥460 ms.Schwartz scored 6.0 (5.0, 6.0) points, all cases≥4 points.All patients were initially treated with metoprolol or propranolol, of which 14 patients were followed up to date, three patients had recurrent syncope, and five patients stopped taking the medicines by themselves.One patient with high-dose metoprolol (LQT2) was treated with mexiletine after recurrent episodes.One patient who was intolerant to high-dose propranolol underwent left cardiac sympathectomy and was followed up after surgery without syncope episodes.None of the patients underwent implantable cardioverter defibrillator implantation. Conclusion:Children with LQTS and syncope symptoms have high positive rate of genetic tests.The genetic results could assist typing of patients with LQTS and guide treatment.Routine electrocardiogram screening in children with syncope may diagnose LQTS earlier and reduce misdiagnosis and missed diagnosis.β-blockers are the cornerstone of treatment for patients with LQTS.Strengthening follow-up management and improving patients′ treatment compliance is conducive to further improving the treatment response rate of patients.