Diagnosing CHD

It's very important to see your doctor right away if you have any of the symptoms or risk factors of coronary heart disease (CHD).

CHD won't go away by itself and it can lead to life–threatening complications. Many of the tests that diagnose CHD are noninvasive, meaning that they don't require a surgical procedure. Once you have a diagnosis, you can begin treatment and get on the road to better health.

How coronary heart disease (CHD) is diagnosed

There are a number of tests that can be used to help diagnose CHD, including EKGs, echocardiograms, and stress tests. Your doctor may start by asking you about your family and medical history and performing a physical exam. To make a diagnosis, he or she may order one or more of the following tests:

• Blood tests: Analyzing blood samples can check your levels of cholesterol, sugar, and proteins. High levels of a substance called C–reactive protein in the blood can indicate inflammation that may raise the risk for CHD.
• Stress tests: Stress tests can help your doctor determine how well your heart works when it's under stress. This test can show potential signs of CHD, including changes in heart rhythm, electrical activity, heart rate, and blood pressure. There are several types of stress tests.

• Exercise stress test—In this test, the electrical activity of your heart is measured by an electrocardiogram (EKG) (see below) while you walk or run on a treadmill or ride a stationary bike. This test helps determine how well your heart handles the work or stress induced by the treadmill or bicycle.
• Nuclear stress test—This can provide information on parts of the heart that don't function normally based on images taken with a camera (single-photon emission computed tomography or positron emission tomography). Using a radio tracing imaging isotope that is injected into your bloodstream, this test is performed by comparing two pictures of your heart—one when the heart is stressed, and one when the heart is at rest. This procedure is used with an exercise stress test or a stress medication if you are unable to exercise to the level necessary to complete the test. The medication simulates the effects of physical activity by increasing blood flow to your heart. Here's how these tests work:

• Nuclear stress test with exercise: You walk on a treadmill or pedal a stationary bike, and the tracer is injected into your bloodstream.
• Nuclear stress test with a pharmacologic agent: A pharmacologic agent (a medication) is injected through the IV, followed by the tracer

• Chest X-ray: This creates an image of the organs and structures inside your chest such as the heart, lungs, and blood vessels, which can help your doctor diagnose heart disease.
• Electrocardiogram (EKG): An EKG measures the electrical activity of your heart. Electrodes (small metal discs) are attached to the skin of each arm and leg and your chest. These are attached to a machine that traces the activity of your heart. This can tell your doctor if you have a regular heartbeat and how fast it is.
• Echocardiogram: This test uses ultrasound to create a picture of the size and shape of your heart and review how well it's working. An echocardiogram can detect restricted blood flow in areas of the heart.
• Computed tomography (CT) scan: A CT scan uses an X-ray machine to take detailed pictures of the heart and create a 3-D image of the entire heart. This test looks for CHD or other heart problems.
• Holter monitoring: This is a portable EKG device that continually monitors your heart's activity for 1 to 2 days or longer. You also write down your activities while you wear the monitor. Your doctor will check the records to see if you’ve had irregular heart beats.
• Single Photon Emission Computed Tomography (SPECT) scan: This imaging test helps doctors evaluate if there’s enough blood flow to your heart and how well your heart is pumping. Tracers are injected into the bloodstream, then a special camera takes pictures of how the tracers flow through your heart.
• Positron emission tomography (PET) scan: This is a test that helps to determine how well blood is flowing in to your heart. The test involves an injection of a radio tracing imaging isotope followed by images taken by a camera.
• Cardiac MRI: Cardiac MRI (magnetic resonance imaging) uses a computer, radio waves, and magnets to create pictures of your heart. This can help detect CHD and other types of heart disease.

If your doctor suspects you have CHD, he or she may recommend that you have additional invasive tests, which may include the following:

• Coronary angiography: This procedure takes X-ray images while a dye is injected to look inside the coronary arteries to detect blockages. A procedure called cardiac catheterization is done to inject the dye into the coronary arteries..
• Cardiac catheterization: In this procedure, a long, thin, flexible tube called a catheter is inserted into a blood vessel in your arm, groin, or neck and threaded into your heart. Through this catheter, doctors conduct diagnostic tests and administer certain treatments.