Dobutamine
Stress Echocardiogram
(DSE,
Dobutamine Stress Echocardiography, Dobutamine
Stress Echo)
What
is a dobutamine stress echocardiogram?
A dobutamine
stress echocardiogram is a diagnostic procedure
that may be used when a physician wants to assess
the heart muscle under stress. If exercise on
a treadmill is not an option (too much stress
on the heart) due to a person’s medical
condition, a physician may use an intravenous
medication called dobutamine. Dobutamine causes
the heart to beat faster and will mimic the effects
of exercise on the heart.
An echocardiogram
is a noninvasive (the skin is not pierced) procedure
used to assess the heart's function and structures.
During the procedure, a transducer (like a microphone)
sends out ultrasonic sound waves at a frequency
too high to be heard. When the transducer is placed
on the chest at certain locations and angles,
the ultrasonic sound waves move through the skin
and other body tissues to the heart tissues, where
the waves echo off of the heart structures. The
transducer picks up the reflected waves and sends
them to a computer. The computer interprets the
echoes into an image of the heart walls and valves.
A dobutamine
stress echocardiogram may utilize one or more
of four special types of echocardiography, as
listed below:
- M-mode echocardiography
This, the simplest type of echocardiography,
produces an image that is similar to a tracing
rather than an actual picture of heart structures.
M-mode echo is useful for measuring heart structures,
such as the heart's pumping chambers, the size
of the heart itself, and the thickness of the
heart walls.
- Doppler echocardiography
This Doppler technique is used to measure and
assess the flow of blood through the heart's
chambers and valves. The amount of blood pumped
out with each beat is an indication of the heart's
functioning. Also, Doppler can detect abnormal
blood flow within the heart, which can indicate
a problem with one or more of the heart's four
valves or with the heart's walls.
- color Doppler
Color Doppler is an enhanced form of Doppler
echocardiography. With color Doppler, different
colors are used to designate the direction of
blood flow. This simplifies the interpretation
of the Doppler technique.
- 2-D (2-dimensional)
echocardiography
This technique is used to visualize the actual
structures and motion of the heart structures.
A 2-D echo view appears cone-shaped on the monitor,
and the real-time motion of the heart's structures
can be observed. This enables the physician
to see the various heart structures at work
and evaluate them.
Other
related procedures that may be used to assess
the heart include resting or exercise electrocardiogram
(ECG or EKG), Holter monitor, signal-averaged
ECG, cardiac catheterization, chest x-ray, computed
tomography (CT scan) of the chest, electrophysiological
studies, magnetic resonance imaging (MRI) of the
heart, myocardial perfusion scans, radionuclide
angiography, and ultrafast CT scan. Please see
these procedures for additional information.
Possible
indications for a dobutamine stress echocardiogram
may include, but are not limited to, the following:
- to assess the heart's
function and structures
- to determine limits
for safe exercise in patients who are entering
a cardiac rehabilitation program and/or those
who are recovering from a cardiac event, such
as a heart attack (myocardial infarction, or
MI) or heart surgery
- to evaluate blood pressure
during stress testing
- to assess stress or
exercise tolerance in patients with known or
suspected coronary artery disease
- to evaluate the cardiac
status of a patient about to undergo surgery
There
may be other reasons for your physician to recommend
a dobutamine stress echocardiogram.
Possible
risks associated with a dobutamine stress echocardiogram
include, but are not limited to, the following:
- chest pain
- severely high blood
pressure
- irregular heartbeats
- dizziness
- nausea and extreme
fatigue
- heart attack (rare)
Patients
who are allergic to or sensitive to medications
or latex should notify their physician.
If you
are pregnant or suspect that you may be pregnant,
you should notify your physician due to risk of
injury to the fetus from a dobutamine stress echo.
If you are lactating, or breastfeeding, you should
notify your physician.
There
may be other risks depending upon your specific
medical condition. Be sure to discuss any concerns
with your physician prior to the procedure.
Certain
factors or conditions may interfere with a dobutamine
stress echocardiogram. These factors include,
but are not limited to, the following:
- smoking or ingesting
caffeine within three hours of the procedure
- beta-blocking medications
may make it difficult to increase the heart
rate
- Your physician will
explain the procedure to you and offer you the
opportunity to ask any questions that you might
have about the procedure.
- You will be asked to
sign a consent form that gives your permission
to do the test. Read the form carefully and
ask questions if something is not clear.
- Notify the physician
if you are allergic to or sensitive to medications
or latex.
- Fasting may be required
before the procedure. Your physician will give
you instructions as to how long you should withhold
food and/or liquids. In some cases, cigarettes
and caffeinated beverages, such as coffee, tea,
and cola may be restricted several hours before
testing.
- If you are pregnant
or suspect that you may be pregnant, you should
notify your physician.
- Notify your physician
of all medications (prescription and over-the-counter)
and herbal supplements that you are taking.
- Notify your physician
if you have a pacemaker.
- Based upon your medical
condition, your physician may request other
specific preparation.
A dobutamine
stress echocardiogram may be performed on an outpatient
basis or as part of your stay in a hospital. Procedures
may vary depending on your condition and your
physician's practices.
Generally,
a dobutamine stress echocardiogram follows this
process:
- You will be asked to
remove any jewelry or other objects that may
interfere with the procedure. You may wear your
glasses, dentures, or hearing aids if you use
any of these.
- You will be asked to
remove clothing from the waist up and will be
given a gown to wear.
- You will be asked to
empty your bladder prior to the procedure.
- An intravenous (IV)
line will be started in your hand or arm prior
to the procedure for injection of medication
and to administer IV fluids, if needed.
- You will lie on your
left side on a table or bed, but may be asked
to change position during the procedure.
- You will be connected
to an ECG monitor that records the electrical
activity of the heart and monitors the heart
during the procedure using small, adhesive electrodes.
Your vital signs (heart rate, blood pressure,
breathing rate, and oxygenation level) will
be monitored during the procedure. The ECG tracing
that will record the electrical activity of
the heart will be compared to the images displayed
on the echocardiogram monitor.
- The room will be darkened
so that the images on the echo monitor can be
viewed by the technologist.
- The technologist will
place warmed gel on your chest and then place
the transducer probe on the gel. You will feel
a slight pressure as the technologist positions
the transducer to get the desired image of your
heart.
- The dobutamine infusion
will begin at a rate determined by your weight.
The rate of the infusion will be increased every
few minutes until you have reached your target
heart rate (determined by the physician based
on your age and physical condition), or until
the maximum dose of dobutamine has been reached.
- After the dobutamine
is started and after each increase in the dobutamine
rate, your blood pressure will be checked, an
ECG tracing will be performed, and echocardiogram
images will be obtained.
- The technologist will
move the transducer probe around on your chest
so that all areas and structures of your heart
can be observed. The different echocardiogram
techniques described above (M-mode, 2-D, Doppler,
and color Doppler) may be used. You will not
be aware of the different techniques except
that during the Doppler or color Doppler, you
may hear a "whoosh-whoosh" sound, which is the
sound of the blood moving through the heart.
- Once you have reached
your target heart rate or the maximum amount
of the dobutamine, the medication will be stopped.
Your heart rate, blood pressure, ECG, and echo
will continue to be monitored for 10 to 15 minutes
until they have returned to the baseline state.
- You should notify the
technologist if you feel any chest pain, breathing
difficulties, sweating, or heart palpitations.
- Once all the images
have been taken, the technologist will wipe
the gel from your chest, remove the ECG electrode
pads, and remove the IV line. You may then put
on your clothes.
You
may resume your usual diet and activities unless
your physician advises you differently.
Generally,
there is no special type of care following a dobutamine
stress echocardiogram. However, your physician
may give you additional or alternate instructions
after the procedure, depending on your particular
situation.
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