What is Sudden Cardiac Death?

Sudden cardiac death (SCD) is a rapid, unexpected death due to cardiac causes. The differential diagnosis includes diseases from all four structural divisions of the heart: the blood vessels, myocardium, valves, and conduction system. Although ischemic heart disease is a common cause of SCD, acute myocardial infarcts and/or coronary thromboses are not always detected and are not required to make the diagnosis of death due to atherosclerotic coronary disease. Some people die suddenly from heart disease with a grossly and microscopically normal heart. Molecular analysis of some of these autopsy-negative, sudden unexplained deaths (SUD) may detect putative cardiac channel mutations. There are three SCD scenarios that are of particular interest to forensic pathologists: sudden cardiac deaths in young athletes, during criminal altercations (homicide by heart attack), and in other hostile environments. In young athletes, most sudden deaths involve cardiac disease and include cardiomyopathies, congenital coronary artery anomalies, myocarditis, and channelopathies. One must, however, consider other causes in these deaths (e.g., commotio cordis, hyperthermia, sickle cell trait). Homicide-by-heart-attack deaths are those in which the cause of death is an acute exacerbation of underlying cardiac disease, however, the manner is homicide because a criminal act triggered the lethal pathologic cascade. A sudden cardiac arrest may occur in hostile locations with resultant trauma (e.g., while driving a motor vehicle). When the event occurs in the bathtub or other body of water, the question of whether the person died naturally from heart disease or unnaturally from trauma (e.g., drowning) often arises. One should not be mislead by the initial physical surroundings of the death (i.e., in a motor vehicle collision, or swimming pool) and fail to distinguish a natural sudden death from an accidental one.