Adenosine Nuclear
Scan
What is a ‘stress test’ and
why is this called a stress test?
The resting heart muscle’s
blood supply needs are usually well met even in the
presence of blocked arteries. When the heart is
stressed either by exercise or chemicals, the demand
for blood increases. The blood flow through the
blocked arteries- while adequate at rest- may not be
able to keep up with the demands of a stressed
heart. This can show up on the pictures of the
heart taken after stress. This is the principle
behind all the stress tests. The word stress test is
used for any means used to increase heart muscle’s
demand for blood. This can be done by exercise or by
chemical means.
What is an Adenosine
nuclear scan?
It is similar to the
exercise
nuclear stress test except for the fact that a
chemical called Adenosine is used to stress the
heart. Adenosine is infused over 4-6 minutes.
Why is a chemical instead of
exercise used to stress the heart?
The Adenosine is used instead
of exercise to stress the heart in the following
situations:
-
If you cannot walk on treadmill for some
reasons.
-
Your EKG
shows an abnormality called left bundle branch block
(LBBB).
-
An adenosine stress test may be a preferable
test for certain people with pacemakers.
How do you prepare for this
test?
The preparation is mostly the
same as for exercise stress test. In addition, you
should not consume caffeine containing beverage for
several hours before the test. Ask your provider how
long you need to be without caffeine before the
test. Caffeine intake before adenosine stress test
affects quality of Adenosine nuclear scan.
What are the shortcomings of
Adenosine nuclear stress test?
Adenosine can cause several
side effects including slow pulse, chest pressure,
facial flushing, ‘weird’ feeling etc. Most of the
side effects should dissipate soon after stopping
Adenosine. In some cases, you may continue to feel
bad for a day or so. If you feel any unusual
symptoms, you should let your provider know.
Adenosine should not be used in patients with
asthma.
Which one is better-
Adenosine stress test or exercise stress test?
As a general rule, if possible,
exercise should be used to stress the heart. This is
the natural, physiological way to increase heart
muscle’s demand for blood. Adenosine is preferred in
certain situations described above.
Back to stress tests
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