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.
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