|
Myocardial
Perfusion Imaging Stress Test
What
is a Myocardial Perfusion Imaging Stress Test?
Myocardial
Perfusion Imaging stress test is usually done at the Roswell office of
Cardiovascular Physicians of North Atlanta or in Nuclear Medicine
Departments at area hospitals. The test involves an injection of a
small amount of radioactive material which circulates in the
bloodstream and shows if your heart muscle is receiving adequate blood
supply under stress and/or rest conditions. The radioactive injection
is a clear liquid called Myoview (Tc99m Tetrofosmin for injection).
Another material which could also be used is called Thallium.
How
safe is a Myocardial Perfusion Stress Test?
Any
stress procedure may have some risks and you should consult your
physician regarding the risks and benefits of this procedure. The
radioactive materials, Myoview and Thallium, have been shown to be
safe with low incidence of adverse reactions. This test and materials
are used routinely worldwide, under physician supervision, for
myocardial perfusion imaging. Neither Myoview nor Thallium are
"dyes", and there should be no serious side effects from
their injection.
Why
would my doctor order a Myocardial Perfusion Imaging Stress Test
instead of a regular stress test?
Under
certain circumstances, a regular stress test may yield indeterminate
results. To improve the diagnositc accuracy, your physician may
request a myocardial perfusion stress test.
How
is the test performed?
The
test usually consists of two parts, after exercising and under resting
conditions. There are many variations for performing the test, which
depend on the department's routine procedure. The entire test may
completed in one day or in two separate days. You will be informed if
the exercise or rest portion will be done first. Myoview will be
administered by injection during peak exercise and once again while
you are at rest.
As
in a regular stress test, ECG electrodes will be attached to your
chest. This will allow the physician to monitor your heart rate
before, during and after you have exercised. A blood pressure cuff
will be placed on your arm to monitor your blood pressure before,
during and after you have exercise. Additionally, an IV line will be
placed in your hand or arm vein to allow for ease of the Myoview
injection. The IV will be removed when the exam is completed.
The
exercise part of the exam is usually done with a treadmill, very
similar to one used at a healthclub. Exercising will begin slowly, and
approximately every three minutes, the pace will gradually increase.
As you exercise, your heart rate and blood pressure will change. This
is normal and remember, you are being closely monitored throughout the
exam. At your peak exercise, Myoview will be injected into the IV and
you be asked to continue exercising for an additional one or two
minutes.
Approximately
fifteen minutes after the exercise is complete, pictures will be taken
of your heart using a special camera able to trace either Myoview or
Thallium that has localized in your heart. You will be asked to lie
down on a special table. The camera will rotate above and around your
chest while special pictures are being taken, which will take
approximately 20 to 30 minutes to complete. You may breathe normally
while the pictures are being taken. It is very importan that you hold
very still while the camera takes pictures of your heart. You will not
receive any radiation from the camera.
After
30 minutes or so, a second injection of Myoview will be given. The
resting pictures are taken in the same manner as the exercise
pictures. Remember, the order in which pictures are taken depends on
the department's routine imaging procedure. The total time needed for
the test may take from two to five hours.
What
happens if you are unable to exercise?
Some
people, due to a variety of disabilities, are unable to exercise
adequately enough on a treadmill machine to acheive a diagnositic test
result. In these cases, the physician may decide to use a drug to
mimic the effect of exercise on the heart (pharmacologic stress).
Drugs
that mimic exercise on a treadmill are commonly used for this purpose.
If you notice any changes in the way you feel or experience any side
effects, notify the individual who is closely monitoring the test.
Are
there any special preparations for the study?
Clothing
You
should wear comfortable, loose-fitting clothing for exercise and
comfortable shoes appropriate for walking.
Food
The
physician will instruct you not to eat or drink anything 4 hours prior
to the scheduled test time. Also, you should not have caffeine 12
hours prior to the study. If you are diabetic or insulin-dependent,
consult with the physician on such dietary restrictions and insulin
use.
Medications
Consult
with the physician regarding whether certain medications should be
taken before, or held until after the test. Certain medications may
interfere with the effectiveness of the study. If you have high blood
pressure, it is important to take your blood pressure medication.
Important
Points to Remember
|
