Study design: This study will compare the occurrence of MCE between patients with overlap syndrome phenotype and patients with a single phenotype (whether Brugada syndrome or Long QT syndrome type 3) in a cohort of patients 12 years of age and older with the SCN5A-E1784K mutation. Eligible patients will be identified nationwide and included retrospectively and prospectively. Occurrence of MCE between the group  overlap syndrome  and the group  single phenotype  will be compared.
In patients expressing the SCN5A-E1784K mutation (Glu1784Lys), cardiovascular risk is difficult to define as the stratification of these patients is challenging. From our experience, major cardiovascular events (MCE) tend to occur more frequently in patients expressing overlap syndrome phenotype (Brugada syndrome and Long QT syndrome type 3)than in patients expressing a single phenotype (whether Brugada syndrome or Long QT syndrome type 3). This trials is led on the impact on Risk Stratification of Overlap Syndrome Phenotype in Patients With E1784K Mutation in SCN5A ( RISKOVER )