长QT13家系的临床表现和心电学特征研究

目的 探讨长QT13 （LQT13）家系临床表现、心电学特点和基因型之间的关系.方法 研究入选了大连医科大学附属第一医院心内科1个LQT13家系,4代人,共有家族成员49例.家族调查包括临床病史、体格检查、心电图、超声心动图.采集44例血样,根据基因检测结果确定基因诊断.进一步采集基因诊断阳性的患者和匹配的健康对照者数字化心电图和动态心电图资料,比较两组心电参数的改变.结果 家系研究示7例临床诊断为先天性长QT综合征（LQTS）.基因诊断9例阳性,包括7例临床确诊病例和2例疑似病例,女6例,男3例.基因突变为KIR3.4基因Gly387Arg突变.校正QT间期（QTc）：440～490 （454±22） ms.女性患者QT间期偏长,好发晕厥,悲伤易诱发晕厥,有时在夜间发作.QT间期450～460ms的患者没有或者只有1次晕厥发生.该家系患者的晕厥首发均在20岁以后,在20～50岁期间晕厥发作频繁,50岁以后几乎不再发作.2例植入起搏器,β受体阻滞剂治疗有效.与健康对照组相比,LQT13患者QT间期延长主要表现在Q波与T波波峰间期（QTp）的延长.T波波峰到T波终点之间的间期（TpTe）没有改变.T波形状的评分（MCS）研究发现,与健康对照组相比T波起始部分的面积增加,T波幅度没有改变.24h动态心电图心率变异性分析发现,LQT13患者低频成份和高频成份比值（LF/HF）比正常对照组降低.结论 KIR3.4基因Gly387Arg突变引起LQT13.该LQT13家系女性患者多见,首发晕厥发生在成年以后,QT间期轻度延长,主要表现在T波起始部分的延长.临床结果相对良性,没有植入型心律转复除颤器（ICD）,随访9年没有患者猝死.

The clinical manifestation and electrocardiograph characteristics of a LQT13 pedigree

Objective To investigate the relationship between the genotype and phenotype in LQT13. Methods A larger long QT syndrome （LQTS） family pedigree including 49 cases in four generations was evalu- ated.Clinical investigations, electrocardiograph （ECG）, ultrasound cardiograph （UCG） were delivered to all family members.Blood samples were taken for the gene screen in 44 members.The digital ECG and dynamic ECG data were collected from LQT13 patients and matched healthy individuals compared. Results Seven ca- ses were diagnosed as LQTS based on clinical evaluation.The KIR3. 4-Gly387Arg mutation was found in 9 af- fected family members, including the 7 cases with positive clinical diagnosis and 2 suspected clinical cases, 6 in female, and 3 male.The QT interval of female patients was relatively longer with frequent syncope.The syncope was easily induced by emotional stress.It may occur during night.Patients with shorter QT interval （450-460 ms） experienced only once or none syncope. The first syncope occurred after their twenties and occurred frequently from twenties to fifties.It seldom occurred after fifties.Pacemaker was implanted in 2 cases. ~-blocker was effec- tive in LQT13.Compared to healthy individuals,the mutation carriers were found to have prolonged QT peak in- terval with a significantly higher T-wave morphology combination score. Low frequency/high frequency ratio of heart rate variability was reduced in LQT13 patients. Conclusion The Kir3.4-Gly387Arg mutation leads to LQT13.Most of LQT13 patients are female.The first syncope attack occurs at their twenties.The QT interval is prolonged slightly with the first part of T wave prolongation.The prognosis of the LQT13 family members is rela- tively benign.No one experienced sudden cardiac death during the 9 years follow-up.