J波综合征发生机制的研究进展

Research progress on mechanisms of J wave syndrome

目的 J波综合征是引起自发性室颤导致心脏性猝死的一个重要原因。虽然J波综合征有多种表型,但其发生机制与心电图表现具有相似性。J波是动作电位1相复极的结果,主要由I_(to)介导的瞬时外向钾电流产生。由于心内膜与心外膜I_(to)通道密度不同,构成了J波产生的生理基础。除了I_(to)外,其它离子通道如I_(Na)、I_(ca)、I_k也参与J波的形成,这提示任何一种离子通道异常都可产生J波。其中,最常见的离子通道病变是基因突变。已有大量实验表明J波综合征与多种离子通道基因突变相关,如SCN5A、CACNA1C、CACNB2、SCNIB、KCNE3。这些突变的离子通道影响心外膜复极,产生2相折返而引发室颤。因此,充分了解J波综合征的发生机制,有助于临床诊断和治疗,降低死亡率。

J wave syndrome has emerged as a significant cause of idiopathic ventricular fibrillation（IVF） responsible for sudden cardiac death. Although J-wave syndrome involves a variety of types, but its mechanism and ECG performance are similar. The J wave is the result of the 1-phase repolarization of the action potential. which is mainly generated by the Ito-mediated transient outward potassium flow. Because of the heterogeneity of Ito density between the endocardium and epicardium, its heterogeneity constitutes the physiological basis of J wave. In addition to Ito,other ion channels such as INa,Ica,Ik are also related to the generation of J waves. So any of anomalies of these ion channels can cause J waves appearing. The most common lesion of ion channel is gene mutation. A large number of experiments have shown that J wave syndrome is associated with a variety of ion channel gene mutations such as SCN5A, CACNA1C, CACNB2,SCN1B, KCNE3 and so on. The mutation affects the epicardium repolarization, resulting in 2-phase reentry,triggering ventricular fibrillation. Therefore, a full understanding the pathomechanism of J wave syndrome,contributing to clinical diagnosis and treatment, reducing the mortality as much as possible.