The Brugada ECG pattern: a marker of channelopathy, structural heart disease, or neither? Toward a unifying mechanism of the Brugada syndrome.

In 1992, Brugada and Brugada introduced a new clinical entity characterized by right precordial ST-segment elevation followed by a negative T-wave and a high incidence of ventricular fibrillation (VF) in the absence of structural heart disease.1 The typical ECG anomaly is currently known as the Brugada ECG pattern and the conglomerate of features as the Brugada syndrome. Over the years, the Brugada syndrome has been recognized as an important cause of sudden cardiac death in young men, especially in Southeast Asia,2 and has attracted much attention from researchers and clinicians alike. This has led to substantial progress in identification of modulating factors of the Brugada ECG pattern, the associated ventricular arrhythmias, and in the risk stratification of patients.3 However, the development of effective therapeutic strategies has lagged behind. Currently, symptomatic treatment with implantable cardioverterdefibrillators (ICDs) is the mainstay in the prevention of sudden cardiac death,3 although it is costly and associated with a high risk of complications.4 The pathophysiological mechanism of the Brugada syndrome remains elusive,5 and no single causal factor appears to link all patients. The Brugada ECG pattern is modulated by genetic mutations and pharmacological agents that alter the function of ion channels active during the early phases of the action potential. Furthermore, signs of right ventricular structural abnormalities are often found in patients with Brugada syndrome. The aim of this study is to review the available literature on the Brugada syndrome in an attempt to provide a unifying hypothesis of the mechanism of the Brugada syndrome. This unifying hypothesis should be able to explain the ECG pattern, the arrhythmogenic mechanism, their modulation by ion channels, and the relation of structural abnormalities to the Brugada syndrome.