Your chest feels heavy, as if you are in a vise and the pain is spreading to your jaw and shoulder. What to do, call 911, then chew a single uncoated full-size 325-mg aspirin.
The reason you need aspirin is the same reason you should call 911. A heart attack is a dynamic event, and early intervention can limit damage. Paramedics can give you oxygen and medication, and they will monitor your blood pressure and heart rhythm to forestall complications. In the hospital, doctors take EKGs and blood tests to see if you are having a heart attack; if so, they will usually try to open the blocked artery with an angioplasty and stent or a clot-busting drug.
Most heart attacks develop when a cholesterol-laden plaque in a coronary artery ruptures. Relatively small plaques, which produce partial blockages, are the ones most likely to rupture. When they do, they attract platelets to their surface. Platelets are the tiny blood cells that trigger blood clotting. A clot builds up on the ruptured plaque. As the clot grows, it blocks the artery. If the blockage is complete, it deprives a portion of the heart muscle of oxygen. As a result, muscle cells die, a heart attack.
Aspirin helps by inhibiting platelets and just a tiny amount is needed to inhibit all the platelets in the bloodstream. Since the clot grows minute by minute, time is of the essence.
Studies show that a chewed aspirin needs only five minutes to reduce TxB2 concentrations by 50% and 14 minutes for the chewed tablet to produce maximal platelet inhibition, versus 26 minutes for an unchewed aspirin swallowed with water.
Aspirin can also help prevent heart attacks in patients with coronary artery disease and in healthy men over 50 years of age. Low doses, between 81 and 325 mg a day, are needed.