Final answer:
A heart attack, or myocardial infarction (MI), occurs when there is a lack of blood flow and oxygen to a region of the heart, resulting in the death of cardiac muscle cells.
Step-by-step explanation:
A heart attack, or myocardial infarction (MI), occurs when there is a lack of blood flow and oxygen to a region of the heart, resulting in the death of cardiac muscle cells. It is commonly caused by the blockage of a coronary artery due to the buildup of atherosclerotic plaque. The blockage restricts blood and oxygen flow to the myocardium and causes tissue death.