A heart attack happens when the flow of oxygen-rich blood in one or more of the coronary arteries, which supply the heart muscle, suddenly becomes blocked, and a section of heart muscle can’t get enough oxygen. The blockage is usually caused when a plaque ruptures. If blood flow isn’t restored quickly, either by a medicine that dissolves the blockage or a catheter placed within the artery that physically opens the blockage, the section of heart muscle begins to die. Be aware of the symptoms!