Risk factors for cardiac events in children with long QT syndrome: a single-center study / 中华实用儿科临床杂志

ABSTRACT

Objective:To identify the risk factors for cardiac events like recurrent syncope and fatal events in children with long QT syndrome (LQTS).Methods:A retrospective review involving 69 children with LQTS with the age of (7.6±4.2) years (43 male patients, 26 female patients) admitted in the Heart Center, Division of Pediatric Cardiology, First Hospital of Tsinghua University from August 2013 to March 2019 was conducted.Medical history, surface electrocardiogram, Doppler echocardiography and screening results of pathogenic genes of each patient were analyzed.Patients were divided into cardiac event group (32 cases) and non-cardiac event group (37 cases) according to the presence or absence of cardiac events like syncope or sudden death.Differences between 2 groups were compared using the independent sample Student′s t test and Chi- square test. Results:There were 32 cases among 69 children (46.4%) had recurrent syncope, involving 2 deaths, 14 cases among 69 children (20.3%) had a positive family history and 8 cases among 69 children (11.6%) had family history of sudden death.There were 52 cases among 69 children (75.4%) had arrhythmias.Among them, 32 patients (46.4%) with ventricular arrhythmia, including 11 cases (15.9%) with torsades de pointes (TdP). Ten LQTS-associated pathogenic or pathogenic pathologic mutations were found in 53 cases among 69 children (76.8%). Children with cardiac events had a younger mean age of onset [(4.7±4.1) years vs.(7.4±3.7) years, t=-2.856, P=0.006], a longer mean corrected QT (QTc) [(529±66) ms vs.(478±52) ms, t=3.537, P=0.001] and a higher incidence of TdP (34.4% vs.0%, P<0.001) compared with those who did not have cardiac events.Pathogenic mutations of KCNQ1 and KCNH2 were more frequent in children with cardiac events (62.5% vs.18.9%, χ2=14.178, P=0.001). Conclusions:Children with LQTS are prone to cardiac events.Children with a younger onset age, a longer QTc duration, malignant ventricular tachycardia and mutations of the KCNQ1 and KCNH2 genes are more frequently complicated by cardiac events.