Diagnosis

Chest pain doesn't always signal a heart attack. But that's what health care providers in the emergency room usually test for first because it's potentially the most immediate threat to your life. They may also check for life-threatening lung conditions — such as a collapsed lung or a blood clot in the lung.

Immediate tests

Some of the first tests a health care provider may order when evaluating chest pain include:

• Electrocardiogram (ECG or EKG). This quick test measures the electrical activity of the heart. Sticky patches (electrodes) are placed on the chest and sometimes the arms and legs. Wires connect the electrodes to a computer, which displays the test results. An ECG can show if the heart is beating too fast, too slow or not at all. Because injured heart muscle doesn't conduct electrical signals in a typical pattern, the ECG may show that you have had or are having a heart attack.
• Blood tests. Blood tests may be done to check for increased levels of certain proteins or enzymes typically found in heart muscle. Damage to heart cells from a heart attack may allow these proteins or enzymes to leak, over a period of hours, into the blood.
• Chest X-ray. An X-ray of the chest can show the condition of the lungs and the size and shape of the heart and major blood vessels. A chest X-ray can also reveal lung problems such as pneumonia or a collapsed lung.
• Computerized tomography (CT) scan. CT scans can spot a blood clot in the lung (pulmonary embolism) or detect an aortic dissection.

Follow-up testing

Depending on the results from the initial tests for chest pain, you may need follow-up testing, which may include:

• Echocardiogram. An echocardiogram uses sound waves to produce a video image of the heart in motion. A small device may be passed down the throat to obtain better views of different parts of the heart.
• Computerized tomography (CT) scan. Different types of CT scans can be used to check the heart arteries for blockages. A CT coronary angiogram can also be done with dye to check the heart and lung arteries for blockages and other problems.
• Stress tests. These measure how the heart and blood vessels respond to exertion, which may indicate if chest pain is heart related. There are many kinds of stress tests. You may be asked to walk on a treadmill or pedal a stationary bike while connected to an ECG. Or you may be given an IV drug to stimulate the heart in a way similar to exercise.
• Coronary catheterization (angiogram) . This test helps health care providers see blockages in the heart arteries. A long, thin flexible tube (catheter) is inserted in a blood vessel, usually in the groin or wrist, and guided to the heart. Dye flows through the catheter to arteries in the heart. The dye helps the arteries show up more clearly on X-ray images and video.