Long Term Prognosis of Drug-Induced Brugada Syndrome

BACKROUND: Patients with a drug-induced Brugada syndrome (BS) are considered at a lower risk than those with the spontaneous type I pattern. Nevertheless, they can present arrhythmic events.

OBJECTIVE: The purpose of this study was to investigate their clinical characteristics, long-term prognosis and risk factors.

METHODS: A consecutive cohort of 343 drug-induced BS patients was included and compared to 78 with spontaneous type I pattern.

RESULTS: Mean age was 40.7±18.3 years. Sudden cardiac death (SCD) was the clinical presentation in 13 (3.8%), syncope in 86 (25.1%) and 244 (71.1%) were asymptomatic. Drug-induced patients were less frequently men (52.5% vs 80.8%, p<0.01), more frequently asymptomatic (71.1% vs 56.4%, p<0.01) and had less ventricular arrhythmias (VA) induced during electrophysiological study (EPS) (13.2% vs 42.4%, p<0.01). A cardioverter defibrillator (ICD) was implanted in 128 patients (37.3%). During a median follow up of 62.5 months (interquartile range: 28.9 - 115.6), 34 patients presented arrhythmic events. Event rate was 1.1% person-year (vs 2.3% person-year in patients with a spontaneous type I, p<0.01). Presentation as SCD and inducible VA were independent risk factors significantly associated with arrhythmic events (adjusted hazard risk (HR) 22.0 and 3.5). Drug-induced BS was related to a better prognosis only in asymptomatic individuals.

CONCLUSIONS: Drug-induced BS has a good prognosis if asymptomatic, however, SCD is possible. Clinical presentation as SCD and inducible VA during EPS are independent risk factors for arrhythmic events. In asymptomatic patients, proband status and inducible VA can help to identify patients at higher risk, but further evidence is needed.