Sudden cardiac death (SCD) is the leading cause of death from out-of-hospital cardiovascular disease worldwide, with an annual incidence of 1.4 per 100,000 in females and 6.8 per 100,000 in males. Most cases of SCD in older patients (>45 years) are caused by atherosclerotic coronary artery disease. SCD in younger patients (<45 years) is caused by inherited cardiovascular diseases, including premature atherosclerosis, primary electrical disease, cardiomyopathy, thoracic aortic aneurysm, and dissection. Primary electrical disease, caused by molecular defects in the ion channels involved in the generation of cardiac action potentials, accounts for approximately 93% of SCDs from a hereditary disease in patients with negative autopsy findings.