WebMD
Medicine Net: Heart Attack
This site from MedicineNet.com provides great information on a myocardial infarction, otherwise known as a heart attack. Includes a definition and description, along with information on causes, symptoms, diagnosis, and treatment options
University of Washington
University of Washington: After Your Heart Attack
This site offers information on how to recognize and prevent a heart attack.
American Heart Association
American Heart Association: Heart Attack
This resource presents brief information defining a heart attack. The article also contains many links to related topics and publications in English and Spanish.