Over 80% of SCD occurs in patients with organic heart disease. However, approximately 10-15% of SCD occurs in the presence of structurally normal heart and the majority of those patients are young. In this group of patients, changes in genes encoding cardiac ion channels produce modification of the function of the channel resulting in an electrophysiological substrate of VA and SCD. Collectively these disorders are referred to as Cardiac Ion Channelopathies. The 4 major syndromes in this group are: The Long QT Syndrome (LQTS), the Brugada Syndrome (BrS), the Short QT Syndrome (SQTS), and the Catecholaminergic Polymorphic VT (CPVT).