This Statistical Brief examines readmissions within 30 days of a hospital stay for heart attack (i.e., acute myocardial infarction (AMI)) among all patients age 18 years and older. Differences in 30-day readmission rates by patient age, sex, and community-level income are presented, along with information on costs of AMI admissions and readmissions and the reason for the readmission. Examining characteristics that explain variability in readmission rates can help to identify opportunities for targeted interventions for hospital patients at risk for readmission, such as patients hospitalized for a heart attack.