Risk stratification of individuals with the Brugada electrocardiogram: a myth or a reality?

One of the leading causes of death in young adults in some countries, Brugada syndrome has been the focus of many clinical and research investigations since 1992.1 Large prospective cohort studies have advanced our knowledge of this syndrome. We now know that Brugada syndrome is an autosomal dominant disease characterized by mutations in the cardiac sodium channel (e.g., SCN5A) that result in overt or concealed ST-segment elevation in the right precordial leads and a high risk of sudden cardiac death in young and otherwise healthy adults.1 Many factors have shown promise for predicting sudden cardiac death in such patients; however, observations in this regard have not been entirely consistent even in the three largest prospective studies of the natural history of this syndrome.2-4 One study2 included 200 patients with Brugada syndrome (130 probands and 70 family members). An electrophysiology study (EPS) was performed in 86 patients and genetic analysis was done in all patients. Cardiac arrest occurred in 11% of patients. The risk of cardiac arrest was highest in patients with spontaneous ST-segment elevation in leads V1 through V3 and a history of syncope. Inducible ventricular arrhythmias on EPS were not predictive of cardiac arrest. The presence of an SCN5A mutation showed 32% sensitivity and 57% specificity in predicting the occurrence of cardiac arrest.2 Another study3 included 547 patients with the Brugada electrocardiogram and no prior cardiac arrest. During a mean follow-up of 24 months, 8% of patients had sudden death or documented ventricular fibrillation. The risk of these events was significantly higher in patients with a history of syncope and those with inducible sustained ventricular arrhythmias on EPS. The risk appeared to be highest in patients who had suffered at least one episode of syncope, had a spontaneously abnormal electrocardiogram, and were inducible on EPS.3 A third study4 included 212 patients with an electrocardiogram characteristic of Brugada syndrome. During a mean follow-up of 40 months, 9% of patients with previous syncope or cardiac arrest had a ventricular arrhythmic event versus 0.8% in asymptomatic patients. Significant predictors of arrhythmic events were a history of aborted sudden death or syncope and spontaneous coved ST-segment elevation in the right precordial leads. Although inducible ventricular arrhythmias on EPS were not found to be a significant predictor