Pérez-Riera Andrés Ricardo, Barbosa-Barros Raimundo, Daminello Raimundo Rodrigo, da Costa de Rezende Barbosa Marianne Penachini, Esposito Sorpreso Isabel Cristina, de Abreu Luiz Carlos
Metodologia da Pesquisa e Escrita Científica da Faculdade de Medicina do ABC, Santo André, São Paulo, Brazil.
Centro Coronariano do Hospital de Messejana Dr. Carlos Alberto Studart Gomes, Fortaleza, Ceará, Brazil.
Indian Pacing Electrophysiol J. 2018 Jan-Feb;18(1):25-35. doi: 10.1016/j.ipej.2017.10.011. Epub 2017 Oct 31.
Congenital long QT syndrome type 3 (LQT3) is the third in frequency compared to the 15 forms known currently of congenital long QT syndrome (LQTS). Cardiac events are less frequent in LQT3 when compared with LQT1 and LQT2, but more likely to be lethal; the likelihood of dying during a cardiac event is 20% in families with an LQT3 mutation and 4% with either an LQT1 or an LQT2 mutation. LQT3 is consequence of mutation of gene SCN5A which codes for the Nav1.5 Na channel α-subunit and electrocardiographically characterized by a tendency to bradycardia related to age, prolonged QT/QTc interval (mean QTc value 478 ± 52 ms), accentuated QT dispersion consequence of prolonged ST segment, late onset of T wave and frequent prominent U wave because of longer repolarization of the M cell across left ventricular wall.
先天性长QT综合征3型（LQT3）在目前已知的15种先天性长QT综合征（LQTS）中，发病率位列第三。与LQT1和LQT2相比，LQT3中心脏事件的发生频率较低，但更有可能致命；在发生心脏事件时，LQT3突变家族的死亡概率为20%，而LQT1或LQT2突变家族为4%。LQT3是由编码Nav1.5钠通道α亚基的SCN5A基因突变引起的，其心电图特征为与年龄相关的心动过缓倾向、QT/QTc间期延长（平均QTc值478±52毫秒）、ST段延长导致QT离散度增加、T波出现较晚以及由于左心室壁M细胞复极化时间延长而频繁出现明显的U波。
