The Brugada syndrome.

The Brugada syndrome describes a subgroup of patients at risk for the occurrence of ventricular fibrillation who have no definable structural heart disease associated with a right bundle branch block conduction pattern and ST-segment elevation in the right precordial leads. This syndrome is caused by genetic defects in the alpha subunit of the sodium channel. This defect causes a reduction in the sodium channel current, which accentuates the epicardial action potential notch leading to ST-segment elevation. Sodium channel blockers can potentiate these findings and screen for patients with intermittent baseline electrocardiographic findings. Because of the poor prognosis of such patients, symptomatic patients should be treated with an implantable cardioverter-defibrillator.