Sudden cardiac death (SCD) accounts for approximately 300,000 cardiac events in the United States each year, representing an overall incidence of 0.1-0.2% per year. Although the vast majority of these may be attributed to coronary atherosclerosis, a wide variety of nonatherosclerotic-related cardiac diseases have been associated with SCD. This review highlights three general categories of cardiac disease not related to atherosclerosis: the cardiomyopathies, inflammatory myocardial diseases, and ion channel disorders. The important role played by genetics in some of these cardiovascular diseases is presented as well as toxic and drug-related etiologies.