|
|
|
 |
|
When You Need to Have
A Stress Test
Your Doctor may refer you for a stress test to help evaluate your risk for coronary
artery disease or to work up symptoms of chest pain.
If you have already been diagnosed with coronary heart disease, a stress test may enable
the doctor to estimate the severity of the blockages. Likewise, if you have just undergone
balloon angioplasty or bypass surgery, a stress test helps the doctors monitor the success
of the procedure as well as determine an appropriate rehabilitation program for you.
What equipment is used? Will I be in pain?
The stress test involves performing a simple exercise (usually a treadmill, although in
Europe a stationary bike is a popular method) while your body is monitored using several
devices. These devices may include an electrocardiograph machine (ECG), an ultrasound echo machine or a blood pressure
cuff.The ECG records your heart's electrical activity from information it receives through
electrodes, which are taped to your back and chest; the connections are painless. An
ultrasound machine may also monitor the heart's activity; this too is a non-invasive and
painless procedure.
The blood pressure cuff is used to constantly monitor your blood pressure; it is similar
to the one you have used in the doctor's office, and is also painless. All of these
monitoring devices are used throughout the stress test.
Sometimes a drug such as adenosine, dobutamine, or persantine is used, instead of a
treadmill, to simulate the heart's reactions to exercise. These drugs are safe and
reasonably well tolerated, and are usually only given when the body is unable to perform
the stress test, for instance if a patient is particularly out of shape, has lost limbs,
or is severely arthritic. They are as reliable for evaluative purposes as the exercise
test.
How is it done? What if it's too hard for me?
During the test, the doctor will gradually increase the speed and incline of the
treadmill. These increases will take place every two to three minutes while the doctor
closely monitors your heart's performance through the various indicators listed above. Do
not be concerned about the "difficulty" of the test, as your doctor will take
your own physical condition into account when determining the levels of the test. If
you're in poor condition or at high risk for coronary artery disease, the increments will
be smaller and more gradual.
Throughout the test, your doctor will mostly be observing the heart's function and your
oxygen flow in response to increased "challenge" to the heart. She or he may
notice changes in your ECG pattern or blood pressure, and/or unusual shortness of breath
or chest pain, all of which are possible symptoms of coronary artery obstruction.
How long does it last?
The stress test itself usually lasts between six and twenty minutes, once you have been
connected to the various monitors.
Where does it take place?
Although a hospital may have a specific testing facility on-site, you will not necessarily
be going to a hospital for your stress test. Some testing facilities are free-standing,
like a regular doctor's office.
Do I have to be hospitalized?
You will not have to be hospitalized for this procedure.
When do I get the results? What could they mean?
Your doctor may provide you with feedback very early in the test, by stopping because she
or he feels it is unsafe for you. This may be because you are severely out of shape, or
because you are clearly showing signs of heart disease. If this is the case, your doctor
may recommend further, more invasive testing such as a coronary angiogram, in which dye is
injected into your arteries and monitored to determine blockages.
If you have a successful test (no abnormal ECG or unusual blood pressure variations) it is
likely that your risk of coronary artery disease is low. Stress tests are able to detect
individuals with heart disease nearly 90% of the time. This does not mean that you have a
nine in ten chance of having "poor results"; it means that, if you actually DO
have heart disease, the test will accurately detect it nine out of ten times.
It should be noted that the stress test is not wholly reliable, and may cause undue alarm.
Of the one in twenty healthy adult patients whose results indicate a risk of heart
disease, the results are "falsely positive" almost a third of the time, meaning
that there is actually no risk of heart disease despite the test's positive results. False
positive results occur more frequently in women. Further testing will be necessary to
determine whether you actually have heart disease.
If you are concerned about the validity of the ECG test, you may wish to discuss it with
your doctor at greater length. You will not be diagnosed with coronary artery disease
simply from the results of a stress test. |
