Sudden cardiac death (SCD) is the most important challenge of moderncardiology. The importance of this problem is stressed by the fact thatSCD from definition may occur suddenly in individuals that in spite oftheir heart disease are able to live a normal or near normal life. As inpresent times it can be prevented and the knowledge of pathologicalmechanisms as well as the correlation between SCD and associateddiseases and risk factors is crucial.Sudden cardiac death (SCD) is a major public problem accounting forapproximately 20% of all mortality in the western world and up to 50%of overall cardiac mortality in developed countries.The cause of SCD is different in different age groups. The risk factorsare similar to those for coronary heart disease. In recent years, significantadvances have been made in understanding the genetic basis of SCD.The information necessary to establish a diagnosis of SCD isfrequently lacking, because 80 percent of SCDs occur in the homeenvironment, and up to 40 percent of sudden deaths are not witnessed.In most cases of sudden death, cause and manner of death can beestablished, with many attributable to cardiac abnormalities evident atautopsy. A significant number of SCD, however, particularly in youngpeople, remains unexplained following a comprehensive medico-legalinvestigation, including autopsy and laboratory tests.