Major Arrhythmic Events in Asymptomatic Patients with Drug-Induced Brugada Syndrome

Brugada syndrome without spontaneous type 1 ST elevation on ECG (i.e. revealed during ajmaline challenge) displays an excellent prognosis, however sudden death may happen, whose mechanisms and favouring conditions are unknown. Knowledge of the conditions leading to SD may help in still decreasing the low risk of SD in these numerous patients. Describe precisely the context of asymptomatic Brugada Syndrome without spontaneous type 1 ST elevation who experienced major arrhytmic event in order to define favoring factors in this population known with lower mortality rate. The detailed history and ECG of all successive Brugada patients without spontaneous type 1 ST elevation and experiencing or having experienced SD and referred at several University Hospital in France were retrospectively investigated. 23 cases could have been studied (83% men, mean 40 yo) with only 3 having being diagnosed asymptomatic but experiencing later SD (the other had been ressuscitated from initial SD). We could classify these patients in four groups: – patients with a doubtful diagnosis of Brugada (i.e. idiopathic ventricular fibrillation) (n = 6); – Brugada patients with additional structural heart disease (i.e. acute coronary event) (n = 8); – Brugada patients with favouring factors (fever, medications, hypoK, double mutation) (n = 4); - Brugada patients without favouring factors (n = 5) (meaning that true SD rate in this population is very low) ECG during ajmaline challenge frequently showed PVCs (one VT) or QRS widening. In most cases of drug-induced Brugada syndrome patients, other factors may explain the occurrence of SD (associated cardiomyopathy, prohibited medications, fever, hypoK), thus true SD rate in patients without such factors is very low.