Clinical differences between drug-induced type 1 Brugada pattern and syndrome.

Background: Diagnosis of Brugada syndrome (BrS) may be established by exposing a Type 1 Brugada pattern using a sodium channel blocker. Data on the outcomes of different patient populations with drug-induced Type 1 Brugada pattern are limited. The present study reports on the characteristics and outcome of subjects with ajmaline induced Type 1 Brugada pattern.

Methods: A multicenter retrospective study including all consecutive cases of ajmaline-induced Type 1 Brugada pattern from seven centers.

Results: A total of 260 patients (69.9% males, mean age 43.4 ± 13.5) were included. Additional characteristics included history of syncope ( = 56, 21.5%), family history of BrS ( = 58, 22.3%) or sudden cardiac death ( = 47, 18.1%) and ventricular fibrillation ( = 3, 1.2%). Patients were divided into those meeting current diagnostic criteria for drug-induced BrS (DIBrS) and compared to the drug-induced Brugada pattern (DIBrECG). Females were significantly overrepresented in the DIBrS group ( = 50, 40% vs.  = 29, 21.5%,  = .001). A significantly higher prevalence of type 2/3 Brugada ECG at baseline was found in the DIBrECG group ( = 108, 80.8% vs.  = 75, 60% in the DIBrS,  = .026). During a median follow up of three (IQR 1.50-5.32) years, a single event of significant arrhythmia occurred in the DIBrS group.

Conclusion: Less than half of subjects with ajmaline-induced Brugada pattern met current criteria for BrS. These individuals had very low rate of adverse outcomes during a follow up of 3 years, irrespective of the indication for the test or eligibility for the BrS diagnosis.