布鲁格达氏症候群

布鲁盖达氏症候群（Brugada syndrome，BrS）也称为「突然猝死症」，是一种心脏遗传病。由于心脏电流出现异常，严重的能够引致心脏衰竭或猝死。此症是泰国和寮国当地年轻人在没有明显心脏病下突然猝死的主因。
在1989年首次通过心电图在心搏停止的生还者身上发现布鲁盖达氏症候群。
遗传和病理生理学.
大约20%的个案都由心肌细胞基因突变所引起。此基因，名叫SCN5A，在某些个案，此症特殊心脏跳动的情况是可以通过心电图观察出来。
病理机制.
布鲁格达氏症候群患者的心律异常通常是危及生命的心律不整，如心室颤动或多形性心室心搏过速，病人也有可能因为较不严重的心律不整而心搏过速，如房室结重入性心搏过速，或心搏过慢，例如窦房结功能不良。因遗传导致这些心律不整的机转，有数种理论。
Na. The sodium current is a major contributor to the characteristic flow of electrical charge across the membrane of heart muscle cells that occurs with each heartbeat known as the action potential. "I"Na causes the initial rapid upstroke of the action potential (phase 0), and decreasing the early peak current, as occurs in BrS-associated genetic variants, leads to slowing of the electrical conduction through the heart muscle. This slow conduction allows 'short circuits' to form, blocking the waves of electrical activity in some areas while allowing the waves to pass in others in a phenomenon known as wavebreak. Given the right circumstances, this wavebreak can allow the waves of electricity to perform a U-turn within the muscle, travelling in the reverse direction before beginning to rapidly circle around a point, referred to as re-entry, and causing an abnormal heart rhythm. Those who support this view (known as the depolarisation hypothesis) argue that conduction slowing may explain why arrhythmias in those with Brugada syndrome tend to occur in middle age, when other factors such as scarring or fibrosis that accompany old age have exacerbated the tendency to conduction slowing caused by the genetic mutation.
Others suggest that the main cause of arrhythmias is a difference in the electrical properties between the inside (endocardium) and outside (epicardium) of the heart (known as the repolarisation hypothesis). The shape of the action potential differs between the epicardium and the endocardium. The action potential in cells from the epicardium shows a prominent notch after the initial spike due to a transient inward current. This notch is far less evident in cells from the endocardium, and the difference between the endocardium and epicardium are most clearly seen in the right ventricle. In those with Brugada syndrome, these differences are increased, creating a brief period within each cardiac cycle when current flows from the endocardium to the epicardium creating the characteristic ECG pattern. The differences in electrical properties between the epi- and endocardium are described as a 'transmural dispersion of repolarisation" which if large enough can lead to electrical impulses becoming blocked in some regions but not others. Once again, this wavebreak can allow the waves of electricity which usually travel in only one direction to instead begin circling around a point as a re-entrant circuit, causing an arrhythmia.
A further factor promoting arrhythmias in Brugada syndrome is changes to the structure of the heart. Whilst the heart of those with Brugada syndrome may look normal, scarring or fibrosis is often seen in particular regions of the heart, specifically the right ventricular outflow tract. As Brugada syndrome can be caused by mutation in many different genes, it is possible that different mechanisms may be responsible for the arrhythmias seen in different patients.
诊断.
心电图.
布鲁格达氏症候群患者的心电图有一些特征。在胸前导程V1到V3可见ST节段升高，伴有右束支传导阻滞 （RBBB） 表现。可能有心脏内电传导减慢的征象，如PR 间期延长。这些征象可能持续存在，但也有可能仅在特定药物、发烧、运动或其他触发因素时出现。如果做心电图检查时将一些电极放置在与平时不同的位置，尤其是将 V1 和 V2 改放在胸壁的第 1 或第 2 肋间，可能可使这些征象更加明显。
以前曾将布鲁格达氏症候群患者的心电图征象分为三型：
目前建议只有上述第一型心电图模式（不论是自发，或由药物诱发）可用于诊断布鲁格达氏症候群，因为所谓第二型与第三型心电图模式在没有疾病的人中并不罕见。
治疗.
布鲁格达氏症候群的致死原因是心室颤动。因为并无方法预防此症患者发生心室颤动，故治疗有赖于在致命的心律不整导致病人即将死亡时将其遏止。可以植入去颤器（可以持续监测心脏节律，如发现有心室颤动便进行去颤）。有冠状动脉疾病风险的病人在植入去颤器前可能需要先进行血管摄影检查。