INTRODUCTION: Recent progress in molecular biology led to the identification of the genes involved in various cardiac arrhythmias causing syncope and sudden death in young people. EXEGESIS: This article briefly describes the clinical features and the genes associated with the congenital long QT syndrome, the short QT syndrome, Brugada's syndrome, catecholaminergic polymorphic ventricular tachycardias and arrhythmogenic right ventricular dysplasia. CONCLUSION: Identification of genetic variations that cause cardiac tachyarrhythmias can help to identify at risk-patients and to propose clinical follow-up and preventive therapy. Further studies are needed to discover other cardiac genetic disorders and to understand cellular mechanisms involved in these diseases.