Among the commonly understood socioeconomic determinants of health, social change, disorganization, and poverty have been associated with an increased risk of morbidity and mortality. One of the postulated mechanisms through which these determinants have been linked to health and illness is their relationship to social support. The health determinant, social isolation or lack of a social support network (SSN), and its effects on premature mortality after acute myocardial infarction mandate further scrutiny by the cardiovascular community for several reasons. First, as a predictor of 1-year mortality, low SSN is equivalent to many of the classic risk factors, such as elevated cholesterol level, tobacco use, and hypertension. Second, treatment of acute myocardial infarction is costly. Because low social support is associated with an increased 1-year mortality, neglecting the role of the SSN may diminish the possible gains accrued during acute-phase treatment. Therefore, lack of an SSN should be considered a risk factor for subsequent morbidity and mortality after a myocardial infarction. Finally, cardiac rehabilitation programs and other extant prevention strategies can be better used to reduce mortality after myocardial infarction. This article systematically reviews recent evidence related to SSNs to provide an update on the role of social support in cardiovascular disease-related outcomes.