[Brugada syndrome].

Brugada syndrome is characterized clinically by the onset of syncopes or sudden death related to ventricular tachyarrhythmias in patients with a structurally normal heart. Its electrocardiographic features include right bundle branch bloc and ST-segment elevations in the precordial leads V1-V3. The estimated prevalence is 1 per 1000 in Asian countries and probably lower elsewhere: Asia is probably a birthplace of the syndrome. Its transmission is autosomal dominant with variable penetrance. Mutations have been identified in a gene coding for the alpha subunit of the sodium channel (SCN5A) in only 25% of cases. These genetic abnormalities cause a reduction of the density of the sodium current and explain the aggravation of electrocardiographic abnormalities caused by antiarrhythmic sodium channel blockers. Prognosis is very serious in symptomatic patients: prevention of sudden death requires implantation of an automatic defibrillator. The treatment decision is much more difficult for asymptomatic subjects with no family history.