What is the Brugada syndrome?

In 1992, Brugada and Brugada reported a distinct subgroup of patients with episodes of "idiopathic"polymorphic ventricular tachycardia or ventricular fibrillation characterized by a unique electrocardiographic (ECG) pattern, which consisted of right bundle branch block and ST-segment elevation from V1 to V2-V3. As in patients with long QT syndrome, the ECG changes and the ventricular electrical instability could not be explained by structural heart disease, myocardial ischemia, or electrolyte disturbances. The syndrome can be inherited and predominantly affects males. Clinical presentation includes cardiac arrest or syncope caused by rapid ventricular tachycardia or fibrillation characteristically occurring at rest or during sleep. The clinical outcome of affected patients is poor unless they receive an implantable cardioverter defibrillator. The ECG pattern and the electrical ventricular instability have been explained by the dispersion of repolarization between the right ventricular epicardium and endocardium, which predisposes to local reexcitation of myocytes with different action potential durations. A disease-causing missense mutation in the cardiac sodium channel gene SCN5A has been recently reported in patients with Brugada syndrome. It is mandatory for the clinician to carefully rule out any organic heart disease before suggesting a diagnosis of Brugada syndrome, because the typical ECG pattern with the risk of sudden arrhythmic death is also observed in patients with structural heart diseases in the setting of arrhythmogenic right ventricular cardiomyopathy.