Analysis of misdiagnosis and mistreatment in congenital long QT syndrome

LI Guixia; XU Xin; WANG Xianmin; JI Xuehong; ZHU Shuyao; HE Shuang; HE Chuan; LYU Tiewei

doi:10.3969/j.issn.1002-3429.2025.19.003

Abstract：Objective To explore the clinical characteristics,causes of misdiagnosis,and preventive strategies for congenital long QT syndrome(cLQTS).Methods A retrospective analysis was conducted on the clinical data,genetic reports and treatment processes of 2 patients with misdiagnosed cLQTS from June to November 2023.Results Both children complained of repeated loss of consciousness and were misdiagnosed with non-cardiogenic syncope and epilepsy respectively.Under sinus rhythm,surface electrocardiogram(ECG)examination indicated prolonged QT interval after correction(QTc).During the attack,the ECG suggested torsional pointed-point ventricular tachycardia.Eventually,gene sequencing confirmed that all were variations of the KCNH2 gene.The clinical manifestations,ECG characteristics and genetic results of the 2 children patients were consistent with the diagnosis of cLQTS,and the misdiagnosis lasted 5 years and 2 years respectively.Two children were diagnosed and treated with anti-arrhythmic drugs.Their QTc was significantly shortened compared with that before intervention.They were followed up in the Outpatient Department for more than one year and there were no recurrent episodes of loss of consciousness.Conclusion cLQTS is usually characterized by loss of consciousness as the main manifestation,with a high risk of sudden death.However,its attacks are recurrent and self-limiting,and most patients first present to the Department of Neurology,making it prone to misdiagnosis as epilepsy or non-cardiogenic syncope,resulting in a relatively high misdiagnosis rate.Mastering the clinical characteristics of cLQTS and conducting surface ECG in a timely manner,as well as completing genetic testing as early as possible,is the key to reducing and avoiding misdiagnosis and mistreatment.