A heart attack occurs when the blood flow that brings oxygen to the heart muscle is severely reduced or cut off completely. This happens because coronary arteries that supply the heart muscle with blood flow can slowly become narrow from a buildup of fat, cholesterol and other substances that together are called plaque. This slow process is known as atherosclerosis. When a plaque in a heart artery breaks, a blood clot forms around the plaque. This blood clot can block the blood flow through the heart muscle. When the heart muscle is starved for oxygen and nutrients, it is called ischemia. When damage or death of part of the heart muscle occurs as a result of ischemia, it is called a heart attack or myocardial infarction (MI).
- Chest discomfort. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes, or that goes away and comes back. It can feel like uncomfortable pressure, squeezing, fullness or pain.
- Discomfort in other areas of the upper body. Symptoms can include pain or discomfort in one or both arms, the back, neck, jaw or stomach.
- Shortness of breath with or without chest discomfort.
- Other signs may include breaking out in a cold sweat, nausea or lightheadedness.
To diagnose a heart attack, an emergency care team will ask you about your symptoms and begin to evaluate you. The diagnosis of the heart attack is based on your symptoms and test results. Tests to diagnose a heart attack include:
- Electrocardiogram (ECG). An electrocardiogram records electrical signals as they travel through your heart. An ECG can often reveal evidence of a previous heart attack or one that’s in progress.
- Blood tests. Blood may be drawn to measure levels of cardiac enzymes that indicate heart muscle damage.
- Echocardiogram. An echocardiogram uses sound waves to produce images of your heart. It can be used during and after a heart attack to learn how the heart is pumping and what areas are not pumping normally. The “echo” can also tell if any structures of the heart (valves, septum, etc.) have been injured during the heart attack.
- Cardiac catheterization may be used during the first hours of a heart attack if medications are not relieving the ischemia or symptoms. It can be used to directly visualize the blocked artery and help your doctor determine which procedure is needed to treat the blockage.
Once heart attack is diagnosed, treatment begins immediately, possibly in the ambulance or emergency room. Drugs and surgical procedures are used to treat a heart attack. The goal of treatment is to limit heart muscle damage.
Drugs used during a heart attack may include:
- Aspirin to prevent blood clotting that may worsen the heart attack
- Other antiplatelets, such as Brilinta, Effient, or Plavix, to prevent blood clotting
- Thrombolytic therapy (“clot busters”) to dissolve any blood clots in the heart’s arteries
- Any combination of the above