A1427S Missense Mutation in SCN5A Causes Type 1 Brugada Pattern, Recurrent Ventricular Tachyarrhythmias and Right Ventricular Structural Abnormalities

A 66- year-old male presented with recurrent syncope and ventricular fibrillation arrest twenty years ago, for which an implantable cardioverter defibrillator was inserted. Electrocardiography showed a Type 1 Brugada pattern. He fulfilled the diagnostic criteria for definite Brugada syndrome, according to the Shanghai Score System, proposed in 2016. Flecainide challenge test was positive, and genetic analysis revealed an A1427S missense mutation in the SCN5A gene. Magnetic resonance imaging showed right ventricular wall thinning but no additional abnormalities that would suggest a diagnosis of arrhythmogenic right ventricular dysplasia. Examination of the international classification of disease (ICD) records revealed several instances of arrhythmias, including one episode of supraventricular tachycardia (SVT), and four episodes of ventricular tachycardia (VT). In response, the patient was placed on chronic quinidine treatment at a dose of 200 mg twice a day, after which no further episodes of arrhythmias were observed. This illustrates that sodium channel mutation can cause both Brugada syndrome and structural abnormalities in the right ventricle.