Causes of a Heart Attack
Causes of a Heart Attack The blockage is caused by a buildup of plaque in the arteries ( atherosclerosis ). Plaque is made up of deposits, cholesterol , and other substances. When a plaque breaks (ruptures), a blood clot quickly forms. The blood clot is the actual cause of the heart attack. If the blood and oxygen supply is cut off, muscle cells of the heart begin to suffer damage and start to die. Irreversible damage begins within 30 minutes of blockage. The result is heart muscle affected by the lack of oxygen no longer works as it should.