Emergency testing for a heart attack

After you call 911 for a heart attack, paramedics will quickly assess your heart rate, blood pressure, and breathing rate. They also will place electrodes on your chest for an electrocardiogram (EKG, ECG) to check your heart's electrical activity.

When you arrive at the hospital, the emergency room doctor will take your history and do a physical exam, and a more complete ECG will be done. A technician will draw blood to test for cardiac enzymes, which are released into the bloodstream when heart cells die.

If your tests show that you are at risk of having or are having a heart attack, your doctor will probably recommend that you have cardiac catheterization. The doctor can then see whether your coronary arteries are blocked and how your heart functions.

If an artery appears blocked, angioplasty—a procedure to open up clogged arteries—may be done during the catheterization. Or you will be referred to a cardiovascular surgeon for coronary artery bypass graft surgery.

If your tests do not clearly show a heart attack or unstable angina and you do not have other risk factors (such as a previous heart attack), you will probably have other tests. These may include a cardiac perfusion scan or SPECT imaging test.

If your tests do not show signs of a heart attack but your doctor thinks you have unstable angina and may be in danger of having a heart attack, you will be admitted to the hospital.

Testing after a heart attack

From 2 to 3 days after a heart attack or after being admitted to the hospital for unstable angina, you may have more tests. (Even though you may have had some of these tests while you were in the emergency room, you may have some of them again.)

Doctors use these tests to see how well your heart is working and to find out whether undamaged areas of the heart are still receiving enough blood flow.

These tests may include:

• Echocardiogram (echo). An echo is used to find out several things about the heart, including its size, thickness, movement, and blood flow.
• Stress electrocardiogram (such as treadmill testing). This test compares your ECG while you are at rest to your ECG after your heart has been stressed, either through physical exercise (treadmill or bike) or by using a medicine.
• Stress echocardiogram. A stress echocardiogram can show whether you may have reduced blood flow to the heart.
• Cardiac perfusion scan. This test is used to estimate the amount of blood reaching the heart muscle during rest and exercise.
• Cardiac catheterization. In this test, a dye (contrast material) is injected into the coronary arteries to evaluate your heart and coronary arteries.
• Cardiac blood pool scan. This test shows how well your heart is pumping blood to the rest of your body.
• Cholesterol test. This test shows the amounts of cholesterol in your blood.