BACKGROUND: Age is an important determinant of outcomes for patients with acute coronary syndromes. However, community practice reveals a disproportionately lower use of cardiovascular medications and invasive treatment even among elderly patients who would stand to benefit. Limited trial data are available to guide care of older adults, which results in uncertainty about benefits and risks, particularly with newer medications or invasive treatments and in the setting of advanced age and complex health status. METHODS AND RESULTS: Part II of this American Heart Association scientific statement summarizes evidence on presentation and treatment of ST-segment-elevation myocardial infarction in relation to age (< 65, 65 to 74, 75 to 84, and > or = 85 years). The purpose of this statement is to identify areas in which the evidence is sufficient to guide practice in the elderly and to highlight areas that warrant further study. Treatment-related benefits should rise in an elderly population, yet data to confirm these benefits are limited, and the heterogeneity of older populations increases treatment-associated risks. Elderly patients with ST-segment-elevation myocardial infarction more often have relative and absolute contraindications to reperfusion, so eligibility for reperfusion declines with age, and yet elderly patients are less likely to receive reperfusion even if eligible. Data support a benefit from reperfusion in elderly subgroups up to age 85 years. The selection of reperfusion strategy is determined more by availability, time from presentation, shock, and comorbidity than by age. Additional data are needed on selection and dosing of adjunctive therapies and on complications in the elderly. A "one-size-fits-all" approach to care in the oldest old is not feasible, and ethical issues will remain even in the presence of adequate evidence. Nevertheless, if the contributors to treatment benefits and risks are understood, guideline-recommended care may be applied in a patient-centered manner in the oldest subset of patients. CONCLUSIONS: Few trials have adequately described treatment effects in older patients with ST-segment-elevation myocardial infarction. In the future, absolute and relative risks for efficacy and safety in age subgroups should be reported, and trials should make efforts to enroll the elderly in proportion to their prevalence among the treated population. Outcomes of particular relevance to the older adult, such as quality of life, physical function, and independence, should also be evaluated, and geriatric conditions unique to this age group, such as frailty and cognitive impairment, should be considered for their influence on care and outcomes. With these efforts, treatment risks can be minimized, and benefits can be placed within the health context of the elderly patient.