Brugada syndrome is an electrical heart disorder characterized by: ST segment elevation in the right precordial leads (V1 to V3), complete or incomplete blockade of the right branch, and susceptibility to ventricular tachycardia and a sudden death.
The typical electrocardiogram is usually intermittent and the disease shows a great geographic variability, so its prevalence is difficult to estimate. In Eastern countries the prevalence is 1/700-1/800. The prevalence in Europe and the United States is lower: 1/3,300-1/10,000.
The disease is more frequent in men than in women (with a sex ratio of 8:1) and it usually manifests during the third or fourth decade of life.
Brugada syndrome usually manifests itself with syncopes at rest or during sleep. In some cases, tachycardia does not resolve spontaneously and can cause sudden death. The triggers of arrhythmia are: fever, large meals or certain drugs (including antiarrhythmics or antidepressants). In some cases, the ECG tracing is not evident and therefore does not allow diagnosis. Therefore, to confirm/rule out the diagnosis the administration of class IC antiarrhythmic drugs is necessary.
Some cases have been described where the inheritance is autosomal dominant. The disease can develop due to mutations in five genes: SCN5A, GPD1-L, CACNA1C, CACNB2, SCN1B, KCNE3 and SCN3B.
The diagnosis is based on the clinical examination and the electrocardiogram (including the test with the IC drugs).
Most patients are asymptomatic, between 20 and 30% have syncopes and 8-12% suffer at least one cardiac arrest (which can cause sudden death). The presence of a typical spontaneous ECG pattern and having a history of syncope constitute risk factors.
The use of an implantable automatic defibrillator (ICD) is the only therapeutic option of proven efficacy for the primary and secondary prophylaxis of sudden death. Therefore, the identification of individuals with a high risk is one of the main objectives in the clinical evaluation.
Gene or region studied