Sudden cardiac death (SCD) describes the unexpected natural death from a cardiac cause within a short time period, generally 1 hour or lesser from the onset of symptoms, often due to a cardiac dysrhythmia. Overall, the most common cause of SCD is coronary artery disease but for patients aged younger than 35 years, the most common cause of SCD is a dysrhythmia in the setting of a structurally normal heart. This article will review the background, diagnosis, and management of the common hereditary channelopathies and cardiomyopathies associated with an increased risk of SCD in patients without ischemic heart disease.