Department of Pediatrics, Steven and Alexandra Cohen Children's Medical Center of New York, New Hyde Park, USA.
Am J Cardiol. 2012 May 15;109(10):1459-65. doi: 10.1016/j.amjcard.2012.01.361. Epub 2012 Feb 21.
There is insufficient knowledge concerning long-QT (LQT) 3 in the pediatric population to determine whether recommendations for more aggressive therapy in these patients are appropriate. An international multicenter review of 43 children with cardiac sodium channel (SCN5A) mutations and clinical manifestations of LQT syndrome without overlap of other SCN5A syndromes was undertaken to describe the clinical characteristics of LQT3 in children. Patients were aged 7.6 ± 5.9 years at presentation and were followed for 4.7 ± 3.9 years. There was significant intrasubject corrected QT interval (QTc) variability on serial electrocardiography. Forty-two percent presented with severe symptoms or arrhythmia and exhibited longer QTc intervals compared to asymptomatic patients. None of the 14 patients who underwent primary prevention implantable cardioverter-defibrillator (ICD) implantation received appropriate shocks in 41 patient-years of follow-up, while 2 of 6 patients who underwent secondary prevention ICD implantation received appropriate shocks in 30 patient-years of follow-up. Half of patients who underwent ICD implantation experienced inappropriate shocks or ICD-related complications. Mexiletine significantly shortened the QTc interval, and QTc shortening was greater in patients with longer pretreated QTc intervals. Two ICD patients with frequent appropriate ICD shocks showed immediate clinical improvement, with elimination of appropriate ICD shocks after mexiletine loading. In conclusion, severe symptoms are common in children with LQT3 and are associated with longer QTc intervals. ICD implantation is associated with significant morbidity. Mexiletine shortens the QTc interval, and it may be beneficial.
目前关于儿科人群长 QT 综合征（LQT）3 的知识还不够充分，无法确定是否应建议这些患者采取更积极的治疗方法。我们进行了一项国际性多中心回顾性研究，共纳入 43 例存在心脏钠离子通道（SCN5A）突变和 LQT 综合征临床表现但无其他 SCN5A 综合征重叠的儿童患者，旨在描述儿童 LQT3 的临床特征。患者的年龄在就诊时为 7.6 ± 5.9 岁，平均随访 4.7 ± 3.9 年。连续心电图检查显示存在明显的个体内校正 QT 间期（QTc）变异性。42%的患者有严重症状或心律失常，其 QTc 间期较无症状患者更长。在 41 患者年的随访中，14 例接受了一级预防植入式心脏转复除颤器（ICD）植入的患者无一例发生适当电击，而 6 例接受二级预防 ICD 植入的患者中有 2 例在 30 患者年的随访中发生了适当电击。植入 ICD 的半数患者经历了不适当电击或与 ICD 相关的并发症。美西律显著缩短了 QTc 间期，且 QTc 缩短程度与预处理 QTc 间期较长的患者更显著。2 例 ICD 患者频繁发生适当 ICD 电击，而 ICD 电击后即刻出现了临床改善，在给予美西律负荷剂量后，消除了适当 ICD 电击。总之，LQT3 患儿的严重症状常见，且与较长的 QTc 间期有关。ICD 植入与明显的发病率相关。美西律可缩短 QTc 间期，可能有益。
