Tests and diagnosis

By Mayo Clinic Staff

Ideally, your doctor should screen you during regular physical exams for risk factors that can lead to a heart attack.

If you're having a heart attack or suspect you're having one, your diagnosis will likely happen in an emergency setting. You'll be asked to describe your symptoms and will have your blood pressure, pulse and temperature checked. You'll be hooked up to a heart monitor and will almost immediately start to have tests done to see if you are indeed having a heart attack.

The medical staff will listen to your heart and lung sounds with a stethoscope. You'll be asked about your health history and the history of heart disease in your family. Tests will help check if your signs and symptoms, such as chest pain, signal a heart attack or another condition. These tests include:

  • Electrocardiogram (ECG). This is the first test done to diagnose a heart attack. It's often done while you are being asked questions about your symptoms and often by the first responders from emergency medical services. This test records the electrical activity of your heart via electrodes attached to your skin. Impulses are recorded as waves displayed on a monitor or printed on paper. Because injured heart muscle doesn't conduct electrical impulses normally, the ECG may show that a heart attack has occurred or is in progress.
  • Blood tests. Certain heart enzymes slowly leak out into your blood if your heart has been damaged by a heart attack. Emergency room doctors will take samples of your blood to test for the presence of these enzymes.

Additional tests

If you've had a heart attack or one is occurring, doctors will take immediate steps to treat your condition. You may also undergo these additional tests:

  • Chest X-ray. An X-ray image of your chest allows your doctor to check the size of your heart and its blood vessels and to look for any fluid in your lungs.
  • Echocardiogram. This test uses sound waves to produce an image of your heart. During an echocardiogram, sound waves are directed at your heart from a transducer, a wand-like device, held on your chest. The sound waves bounce off your heart and are reflected back through your chest wall and processed electronically to provide video images of your heart. An echocardiogram can help identify whether an area of your heart has been damaged by a heart attack and isn't pumping normally or at peak capacity.
  • Coronary catheterization (angiogram). This test can show if your coronary arteries are narrowed or blocked. A liquid dye is injected into the arteries of your heart through a long, thin tube (catheter) that's fed through an artery, usually in your leg or groin, to the arteries in your heart. As the dye fills your arteries, the arteries become visible on X-ray, revealing areas of blockage. Additionally, while the catheter is in position, your doctor may treat the blockage by performing an angioplasty, also known as coronary artery balloon dilation, balloon angioplasty and percutaneous coronary intervention. Angioplasty uses tiny balloons threaded through a blood vessel and into a coronary artery to widen the blocked area. In most cases, a mesh tube (stent) is also placed inside the artery to hold it open more widely and prevent re-narrowing in the future.
  • Exercise stress test. In the days or weeks after your heart attack, you may also undergo a stress test. Stress tests measure how your heart and blood vessels respond to exertion. You may walk on a treadmill or pedal a stationary bike while attached to an ECG machine. Or you may receive a drug intravenously that stimulates your heart similar to exercise.

    Stress tests help doctors decide the best long-term treatment for you. Your doctor also may order a nuclear stress test, which is similar to an exercise stress test, but uses an injected dye and special imaging techniques to produce detailed images of your heart while you're exercising.

  • Cardiac computerized tomography (CT) or magnetic resonance imaging (MRI). These tests can be used to diagnose heart problems, including the extent of damage from heart attacks. In a cardiac CT scan, you lie on a table inside a doughnut-shaped machine. An X-ray tube inside the machine rotates around your body and collects images of your heart and chest.

    In a cardiac MRI, you lie on a table inside a long tube-like machine that produces a magnetic field. The magnetic field aligns atomic particles in some of your cells. When radio waves are broadcast toward these aligned particles, they produce signals that vary according to the type of tissue they are. The signals create images of your heart.

May. 20, 2014

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