Risk analy- sis is divided into 2 general categories: population risk prediction and individual risk prediction.S2.2.2-41,S2.2.2-50 Conventional epidemiological markers provide insight into probabilities for the development of ischemic heart disease within a general class of subjects, but ade- quately tested and validated profiles for SCA risk strati- fication of individuals in the general population do not presently exist. The challenge of defining SCA risk in individuals derives from a population model character- ized by large numbers of events diluted into a very large denominator (Figure 1). The overall population can be subgrouped into categories based on integration of age, presence and extent of disease, and identification of small, high-risk subgroups within the large denomi- nator general population. Increasing age is a strong predictor of risk for SCA, but it is not linear. Risk in the general population, over time, beginning at 35 years of age has been estimated at 1 per 1000 population per year, increasing from a risk <1000 at the younger end of that spectrum to a higher risk in the elderly.S2.2.2-41 However, an analysis of lifetime risk of SCD, derived from the Framingham data, suggested that the incidence of SCD decreases in later years, especially in people >75 years of age.S2.2.2-51 The data also suggested that SCD is uniformly more common in men than in women at all age groups. 