Antzelevitch C, Yan G X
Masonic Medical Research Laboratory, Utica, NY 13501, USA.
J Electrocardiol. 2000;33 Suppl:33-9. doi: 10.1054/jelc.2000.20321.
The Brugada syndrome is characterized by ST-segment elevation in the right precordial leads, V1-V3 (unrelated to ischemia or structural disease), normal QT intervals, RBBB pattern, and sudden cardiac death, particularly in men of Asian origin. An autosomal dominant mode of inheritance with variable penetrance is generally observed. The only gene mutations thus far linked to the Brugada Syndrome appear in the alpha subunit of the gene that encodes for the cardiac sodium channel, SCN5A. An outward shift in the balance of currents contributing to phase 1 of the right ventricular action potential is thought to underline to electrocardiographic manifestation of the syndrome. Strong sodium channel block, among other modalities, can accentuate the action potential notch in right ventricular epicardial cells, eventually leading to loss of the action potential dome. This results in the development of a large dispersion of repolarization within epicardium as well as between epicardium and endocardium, providing the substrate for the development of phase 2 and cirus movement reentry, which underline VT/VF. Therapy is directed at restoring the balance of current via inhibition of the transient outward current, Ito, and/or stimulation of inward calcium using beta adrenergic agonists, among several strategies.
Brugada综合征的特征为右胸前导联V1 - V3出现ST段抬高（与缺血或结构性疾病无关）、QT间期正常、右束支传导阻滞图形以及心源性猝死，尤其在亚裔男性中更为常见。通常观察到其遗传方式为常染色体显性遗传，具有可变的外显率。迄今为止，唯一与Brugada综合征相关的基因突变出现在编码心脏钠通道SCN5A的基因的α亚基中。导致右心室动作电位1期的电流平衡向外偏移被认为是该综合征心电图表现的基础。强钠通道阻滞剂等因素可加重右心室心外膜细胞动作电位的切迹，最终导致动作电位圆顶消失。这会导致心外膜内以及心外膜与心内膜之间复极化离散度增大，为2相和环形运动折返的发生提供了基础，而这正是室性心动过速/心室颤动的发病机制。治疗策略包括通过抑制瞬时外向电流Ito和/或使用β肾上腺素能激动剂刺激内向钙电流来恢复电流平衡等多种方法。
