- Patients admitted to the University of Pennsylvania Health System who are discharged (or scheduled to be discharged) to their homes with a principal or secondary diagnosis code of International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) 410 (except when the fifth digit was 2) and a length of stay of 1 to 180 days will be considered eligible for the study. Patients must be between 18 and 80 years old and have been discharged to home, 3) Patients are only eligible to enroll in the study for up to 60 days after their hospital discharge for a heart attack.