Ajmaline Testing and the Brugada Syndrome

Brugada syndrome (BrS) diagnosis requires the presence of a typical type 1 ECG pattern. Owing to the spontaneous ECG variability, the real BrS prevalence in the general population remains unclear. The aim of the present study was to evaluate the prevalence of positive ajmaline challenge for BrS in a cohort of consecutive patients undergoing electrophysiological (EP) evaluation for different clinical reasons. All consecutive patients from 2008 to 2019 who underwent ajmaline testing were prospectively included. A total of 2456 patients underwent ajmaline testing, 742 (30.2%) in the context of familial screening (FS) for BrS. Among non FS group (1714) ajmaline testing resulted positive in 186 (10.9%). Indications for ajmaline testing were: suspicious BrS ECG in 23 cases (12.4%), palpitations in 27 (14.5%), syncope in 71 (38.2%), pre-syncope in 7 (3.8%), family history of sudden cardiac death in 18 (9.7%), documented ventricular arrhythmias in 12 (6.5%), unexplained cardiac arrest in 4 (2.2%), atrial fibrillation in 16 (8.5%), brady-arrhythmias in 1 (0.5%) and cerebrovascular accidents in 7 (3.7%). Compared to the overall population, ajmaline testing positive patients were younger (42.8±15.5 vs. 48.9±20.4; p<0.001) and more frequently male (65.1% vs. 56.3%; p=0.023). Implantable cardioverter defibrillator (ICD) was implanted in 84 patients (45.2%). During a median follow up of 42.4 months, 12 appropriate shocks and 13 ICD related complications were reported. In conclusion, the BrS was diagnosed in an unexpected high proportion of patients that underwent ajmaline testing for a variety of cardiovascular symptoms. This can lead to an adequate counseling and clinical management in BrS patients.

Keywords: Brugada syndrome; ajmaline challenge; familial screening; sudden cardiac death.