Garson A, Dick M, Fournier A, Gillette P C, Hamilton R, Kugler J D, van Hare G F, Vetter V, Vick G W
Duke University Medical Center, NC 27710.
Circulation. 1993 Jun;87(6):1866-72. doi: 10.1161/01.cir.87.6.1866.
The Pediatric Electrophysiology Society studied children with the long QT syndrome (LQTS) to describe the features of LQTS in patients less than 21 years old, define potential "low-risk" and "high-risk" subpopulations, and determine optimal treatment.
Patients less than 21 years old were included if either QTc was more than 0.44; they had unexplained syncope, seizures, or cardiac arrest preceded by emotion or exercise; or family history of LQTS. We found 287 patients from 26 centers in seven countries. Mean +/- SD age at presentation was 6.8 +/- 5.6; 9% presented with cardiac arrest, 26% with syncope, and 10% with seizures. Of those with symptoms, 67% had symptoms related to exercise. Family history was positive for long QT interval in 39% and for sudden death in 31%. Hearing loss was present in 4.5%. A normal QTc was present in 6%, and QTc of more than 0.60 was in 13%. Atrioventricular block occurred in 5%, but 13 of 15 patients had second-degree atrioventricular block (2:1), and only two of 287 had complete atrioventricular block. Ventricular arrhythmias were found on 16% of initial routine ECGs: 4% uniform premature ventricular contractions, 5% multiform premature ventricular contractions, 1% monomorphic ventricular tachycardia, and 6% torsade de pointes. Overall, treatment was effective for symptoms in 76% and for ventricular arrhythmias in 60%. There was no difference between propranolol and other beta-blockers in effective treatment. Left stellectomy was performed in nine patients, and defibrillators were implanted in four; no sudden death occurred in these 13 patients. In follow-up (duration, 5.0 +/- 4 years; age, 10.9 +/- 6.3 years), 5% had cardiac arrest, 4% had syncope, and 1% had seizures. The two multivariate predictors of symptoms at follow-up were symptoms at presentation and propranolol failure. Sudden death occurred in 8%; multivariate predictors of sudden death were length of QTc at presentation of more than 0.60 and medication noncompliance.
The appearance of 2:1 atrioventricular block, multiform premature ventricular contractions, and torsade de pointes are relatively more common in children with LQTS than other children and should raise the index of suspicion for LQTS. Because 9% of patients presented with cardiac arrest and no preceding symptoms, perhaps prophylactic treatment in asymptomatic children is indicated. Asymptomatic patients with normal QTc and positive family history may be a low-risk group. Patients with QTc of more than 0.60 are at particularly high risk for sudden death, and if treatment is not effective, consideration should be given to cardiac sympathetic denervation, pacemaker implantation, and perhaps implantation of a defibrillator.
小儿电生理学会对长QT综合征（LQTS）患儿进行了研究，以描述21岁以下患者LQTS的特征，确定潜在的“低风险”和“高风险”亚组，并确定最佳治疗方法。
纳入21岁以下的患者，若其QTc大于0.44；有不明原因的晕厥、癫痫发作或在情绪激动或运动前发生心脏骤停；或有LQTS家族史。我们从七个国家的26个中心找到了287例患者。就诊时的平均年龄±标准差为6.8±5.6岁；9%的患者表现为心脏骤停，26%为晕厥，10%为癫痫发作。在有症状的患者中，67%的症状与运动有关。39%的患者家族史中长QT间期呈阳性，31%有猝死家族史。4.5%的患者有听力损失。6%的患者QTc正常，13%的患者QTc大于0.60。5%的患者发生房室传导阻滞，但15例患者中有13例为二度房室传导阻滞（2:1），287例患者中只有2例为完全性房室传导阻滞。16%的初始常规心电图发现室性心律失常：4%为单形性室性早搏，5%为多形性室性早搏，1%为单形性室性心动过速，6%为尖端扭转型室速。总体而言，76%的患者症状得到有效治疗，60%的患者室性心律失常得到有效治疗。普萘洛尔与其他β受体阻滞剂在有效治疗方面无差异。9例患者接受了左侧星状神经节切除术，4例植入了除颤器；这13例患者均未发生猝死。在随访中（随访时间为5.0±4年；年龄为10.9±6.3岁），5%的患者发生心脏骤停，4%的患者发生晕厥，1%的患者发生癫痫发作。随访时症状的两个多变量预测因素是就诊时的症状和普萘洛尔治疗失败。8%的患者发生猝死；猝死的多变量预测因素是就诊时QTc长度大于0.60和药物治疗依从性差。
2:1房室传导阻滞、多形性室性早搏和尖端扭转型室速在LQTS患儿中比其他儿童相对更常见，应提高对LQTS的怀疑指数。由于9%的患者表现为心脏骤停且无前驱症状，或许对无症状儿童应进行预防性治疗。QTc正常且家族史阳性的无症状患者可能是低风险组。QTc大于0.60的患者猝死风险特别高，如果治疗无效，应考虑进行心脏交感神经去神经支配、起搏器植入，或许还应植入除颤器。
