A heart attack (or myocardial infarction) occurs when the blood flow to part of the heart is blocked, usually by a clot. If the blockage is complete, that part of the heart begins to die. Treatment for a heart attack aims to restore blood flow. Treatment options range from medication to surgical and other procedures (including cardiac catheterization and bypass surgery). The more time passes after the heart attack starts, the more tissue dies. The patient’s survival and long-term prognosis, therefore, depend on prompt diagnosis and effective treatment. A patient who survives a serious heart attack may still require lengthy cardiac rehabilitation and potentially even heart transplantation.