Implications of Associated Atrial Fibrillation in Brugada Syndrome for Sudden Cardiac Death ‒ A Case Series Analysis

BACKGROUND Brugada syndrome (BrS) is a cardiac arrhythmia disorder characterized by ventricular arrhythmias, which can lead to sudden cardiac death (SCD). BrS is also associated with atrial arrhythmias, particularly atrial fibrillation (AF). There is ongoing debate regarding whether treated AF can still precipitate ventricular arrhythmias in patients with BrS. This case series aims to elucidate the prognostic significance of treated AF in BrS patients who experienced SCD. CASE REPORT We report on 2 patients diagnosed with Brugada syndrome (BrS) who presented with atrial fibrillation (AF). Both patients exhibited type I Brugada electrocardiographic patterns, and echocardiographic assessments revealed normal cardiac structure and function. Thyroid function tests and electrolyte levels were within normal ranges. An electrophysiology study (EPS) performed on the first patient demonstrated the induction and termination of AF, but no inducible ventricular arrhythmia was observed. Both patients declined the ablation procedure for AF treatment, opting instead for pharmacologic rhythm control with amiodarone. During follow-up visits every 3 months, neither patient reported palpitations or syncope, and electrocardiography consistently indicated sinus rhythm. Despite this, sudden cardiac death (SCD) occurred in the first patient during the first year of follow-up and in the second patient during the second year of follow-up. CONCLUSIONS Patients with BrS who have treated AF remain at a high risk of SCD. The presence of AF in BrS patients may indicate a specific variant of the SCN5A mutation, which can heighten the risk of ventricular arrhythmias and consequent SCD.