How Is Coronary Artery Disease Diagnosed?

Your doctor will diagnose coronary artery disease (CAD) based on:

• Your medical and family histories
• Your risk factors
• The results of a physical exam and diagnostic tests and procedures

Diagnostic Tests and Procedures

No single test can diagnose CAD. If your doctor thinks you have CAD, he or she will probably do one or more of the following tests.

EKG (Electrocardiogram)

An EKG is a simple test that detects and records the electrical activity of your heart. An EKG shows how fast your heart is beating and whether it has a regular rhythm. It also shows the strength and timing of electrical signals as they pass through each part of your heart.

Certain electrical patterns that the EKG detects can suggest whether CAD is likely. An EKG also can show signs of a previous or current heart attack.

Stress Testing

During stress testing, you exercise to make your heart work hard and beat fast while heart tests are performed. If you can't exercise, you're given medicine to speed up your heart rate.

When your heart is beating fast and working hard, it needs more blood and oxygen. Arteries narrowed by plaque can't supply enough oxygen-rich blood to meet your heart's needs. A stress test can show possible signs of CAD, such as:

• Abnormal changes in your heart rate or blood pressure
• Symptoms such as shortness of breath or chest pain
• Abnormal changes in your heart rhythm or your heart's electrical activity

During the stress test, if you can't exercise for as long as what's considered normal for someone your age, it may be a sign that not enough blood is flowing to your heart. But other factors besides CAD can prevent you from exercising long enough (for example, lung diseases, anemia, or poor general fitness).

Some stress tests use a radioactive dye, sound waves, positron emission tomography (PET), or cardiac magnetic resonance imaging (MRI) to take pictures of your heart when it's working hard and when it's at rest.

These imaging stress tests can show how well blood is flowing in the different parts of your heart. They also can show how well your heart pumps blood when it beats.

Echocardiography

This test uses sound waves to create a moving picture of your heart. Echocardiography provides information about the size and shape of your heart and how well your heart chambers and valves are working.

The test also can identify areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.

Chest X Ray

A chest x ray takes a picture of the organs and structures inside the chest, including your heart, lungs, and blood vessels.

A chest x ray can reveal signs of heart failure, as well as lung disorders and other causes of symptoms that aren't due to CAD.

Blood Tests

Blood tests check the levels of certain fats, cholesterol, sugar, and proteins in your blood. Abnormal levels may show that you have risk factors for CAD.

Electron-Beam Computed Tomography

Your doctor may recommend electron-beam computed tomography (EBCT). This test finds and measures calcium deposits (called calcifications) in and around the coronary arteries. The more calcium detected, the more likely you are to have CAD.

EBCT isn't used routinely to diagnose CAD, because its accuracy isn't yet known.

Coronary Angiography and Cardiac Catheterization

Your doctor may ask you to have coronary angiography (an-jee-OG-ra-fee) if other tests or factors show that you're likely to have CAD. This test uses dye and special x rays to show the insides of your coronary arteries.

To get the dye into your coronary arteries, your doctor will use a procedure called cardiac catheterization (KATH-e-ter-i-ZA-shun). A long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck. The tube is then threaded into your coronary arteries, and the dye is released into your bloodstream. Special x rays are taken while the dye is flowing through your coronary arteries.

Cardiac catheterization is usually done in a hospital. You're awake during the procedure. It usually causes little to no pain, although you may feel some soreness in the blood vessel where your doctor put the catheter.