J波与J波综合征

J波是指心电图上QRS波与ST段之间的圆顶状或驼峰状电位变化。新近临床研究表明，在早期复极综合征、Brugada综合征和特发性心室颤动等心电图中，均存在J波形态、时限和幅度的显著改变，上述与J波密切相关的一系列临床综合征统称为J波综合征。本文详尽阐述了J波的细胞电生理和离子流机制，分析了早期复极综合征、Brugada综合征、心电图下壁导联高大J波相关的心脏性猝死的临床特点及内在机制。

Electrocardiographic J wave and J wave syndromes

J wave,a voltage deflection with a dome or hump morphology immediately following the QRS complex,is the electrocardiographic manifestation of a transmural potential gradient during initial ventricular repolarization that results from the presence of a prominent action potential notch mediated by transient outward potassium current(I to)in the epicardium but not endocardium.J wave is a common electrocardiographic marker shared by the early repolarization syndrome,the Brugada syndrome,and idiopathic ventricular fibrillation or sudden unexplained nocturnal death syndrome.From a mechanistic point of view,these syndromes should be referred to as the J wave syndromes.This review will focus on the ionic and cellular basis for the J wave,the clinical features of the J wave syndromes and the mechanisms underlying arrhythmogenesis that is associated with a prominent J wave.