A nuclear stress test lets doctors see pictures of your heart while you
are resting and shortly after you have exercised. The test can give
information about the size of the heart's chambers, how well the heart
is pumping blood, and whether the heart has any damaged or dead muscle.
Nuclear stress tests can also give doctors information about your
arteries and whether they might be narrowed or blocked because of
coronary artery disease.
How does it work?
This test is almost the same as the exercise stress test,
except doctors will give you a small amount of a radioactive substance
just before the end of the exercise part of the test. This radioactive
substance is not harmful to your body or your organs.
The
results of the nuclear stress test can show doctors if the heart is not
working properly while you are resting, exercising, or both. If the
test shows that blood flow is normal while you are resting but not
normal while you are exercising, then doctors know that your blood flow
to your heart is not adequate during times of stress. The heart
normally pumps more blood during times of physical exertion. If the
test results are not normal during both parts of the test (rest and
exercise), part of your heart is permanently deprived of blood or is
scarred. If doctors cannot see the radioactive substance in one part of
your heart, it probably means that section of heart muscle has died,
either because of a previous heart attack or because the coronary
arteries supplying blood to that area of the heart are blocked.
What should I expect?
Just
like the exercise stress test, you will have small metal disks called
electrodes placed on your chest and back. The electrodes are attached
to wires called leads, which are attached to an electrocardiogram
machine. Doctors will then have you walk on a treadmill.
After
your doctors have the information they need from the exercise part of
the test, you will step off of the treadmill and go into another room.
You will be given an injection of a radioactive substance, and you will
be asked to lie on an examination table, which has a gamma-ray camera
above it. The camera is used to take pictures of your heart. The camera
can pick up traces of the radioactive substance in your body and then
send a picture to a television monitor.
After this
part of the test is over, you can leave the testing area for 3 or 4
hours. Doctors will ask you not to exercise or drink or eat anything
with caffeine, such as coffee, tea, sodas, or chocolate. When you
return, doctors will give you another injection of the radioactive
substance. You will be asked to lie down on the examination table, and
the gamma-ray camera will take pictures of your heart while you are
resting. This will give your doctor an idea of how your heart works
during both exercise and rest.
After the test is over, you may eat, drink, and go back to your normal activities right away.
