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长QT综合征(LQTS)是第一个被发现的遗传性离子通道疾病,LQTS患者可表现出多种临床类型,从终身无症状到婴儿期突然死亡均可发生,易产生恶性室性心律失常,导致晕厥、癫痫样抽搐发作和心脏骤停、心脏性猝死。目前已有的研究表明,LQTS的遗传学发病机制是特定的遗传基因突变导致的心肌除极复极异常。LQTS的发病机制在分子水平上表现为编码离子通道的α亚基和β亚基的15个不同的易感基因的突变。由KCNQ1、KCNH2和SCN5A这3种基因突变导致的LQTS占所有LQTS患者的90%以上,分别称之为LQT1、LQT2和LQT3,其他12个基因突变导致的LQTS只占全部患者的不到10%。LQTS的精准医疗主要体现在β受体阻滞剂的应用。通常认为β受体阻滞剂对LQTS1的治疗效果优于LQTS2和LQTS3。LQT3患者心脏β肾上腺素能受体密度偏低,发作主要与休息及心率慢有关,临床治疗多数推荐钠通道阻滞剂,如美西律、氟卡尼等。
Long-QT Syndrome (LQTS) is the first hereditary ion channel disease to be found. LQTS patients can present a variety of clinical types and can occur from life-long asymptomatic to sudden death in infancy with a predisposition to malignant ventricular arrhythmias , Leading to syncope, epileptic seizures and cardiac arrest, sudden cardiac death. At present, some studies have shown that the genetic mechanism of LQTS is the abnormal depolarization of myocardium caused by specific genetic mutation. The pathogenesis of LQTS appears at the molecular level to be mutations in 15 different susceptible genes that encode the alpha and beta subunits of ion channels. LQTS caused by three gene mutations of KCNQ1, KCNH2 and SCN5A accounted for more than 90% of all LQTS patients, which were called LQT1, LQT2 and LQT3 respectively. The other 12 gene mutations caused LQTS only less than 10% . The precision of LQTS is mainly reflected in the application of β-blockers. Beta blockers are generally considered superior to LQTS1 in the treatment of LQTS2 and LQTS3. LQT3 cardiac β-adrenergic receptor in patients with low density, seizures mainly with rest and slow heart rate, the clinical treatment of most recommended sodium channel blockers, such as mexiletine, flecainide and so on.