A blockage in the heart s arteries may reduce or completely cut off the blood supply to a portion of the heart. This can cause a blood clot to form and totally stop blood flow in a coronary artery, resulting in a heart attack (also called an acute myocardial infarction or MI). Irreversible injury to the heart muscle usually occurs if medical help is not received promptly. Unfortunately, it is common for people to dismiss heart attack symptoms. The American Heart Association and other medical experts say the body likely will send one or more of these warning signals of a heart attack: -Uncomfortable pressure, fullness, squeezing or pain in the center of the chest lasting more than a few minutes. -Pain spreading to the shoulders, neck or arms. The pain may be mild to intense. It may feel like pressure, tightness, burning, or heavy weight. It may be located in the chest, upper abdomen, neck, jaw, or inside the arms or shoulders. -Chest discomfort with lightheadedness, fainting, sweating, nausea or shortness of breath. -Anxiety, nervousness and/or cold, sweaty skin. -Paleness or pallor. -Increased or irregular heart rate. -Feeling of impending doom. Not all of these signs occur in every attack. Sometimes they go away and return. If some occur, get help fast. IF YOU NOTICE ONE OR MORE OF THESE SIGNS IN YOURSELF OR OTHERS, DON T WAIT. CALL EMERGENCY MEDICAL SERVICES (9-1-1) RIGHT AWAY! In the event of cardiopulmonary arrest (no breathing or pulse), call 9-1-1 and begin cardiopulmonary resuscitation (CPR) immediately. The actual diagnosis of a heart attack must be made by a doctor who has studied the results of several tests. The doctor may: -Review the patient s complete medical history. -Give a physical examination. -Use an electrocardiogram (or EKG) to discover any abnormalities caused by damage to the heart. -Use a blood test to detect abnormal levels of certain enzymes in the bloodstream.