|Described below is a regular transthoracic echocardiogram (TTE).
To review two other types of echo, click one one of the
What is Ultrasound?
What is an Echocardiogram?
What is Doppler?
What information does it provide?
How safe is it?
How long does it take?
How quickly do I get the results
and what do they mean?
What is Ultrasound:
Sound is made up of several different frequency waves.
The very high frequency range is inaudible to the human
ear and is known as ultrasound. Ultrasound was used
by the Navy during World War II to detect submarines,
and is widely used by fisherman to help find schools
In each case, an ultrasound machine is used. With the
help of a microphone-shaped device (known as a transducer)
ultrasound waves are created and beamed through water.
When the beam encounters a boundary or interface between
liquid (water) and a solid (submarine or fish) with
a different density or compactness, part of the beam
is reflected back to the transducer. The remaining waves
move through the object and reach the back boundary
between solid and water. Here, some more of the ultrasound
waves are reflected back to the transducer. In other
words, the transducer transmits ultrasound and constantly
receives waves that are reflected back every time the
beam travels from one density to another.
The reflected ultrasound waves are collected and analyzed
by the machine. Determining the amount of time it took for
the beam to travel from and to the transducer (plus the the consistency and changes in position of the different structures that it passed through), the ultrasound
machine can determine the shape, size, density and movement
of all objects that lay in the path of the ultrasound
beam. The information is presented "real time" on a monitor screen
and can also be printed on paper or recorded on tape, a CD or a computer disk. That is how warships
detect submarines, fishermen identify
choice fishing spots, an obstetrician evaluates the
fetus of a pregnant woman, and a cardiologist examines
the heart of a patient.
What is an Echocardiogram:
An echocardiogram is a test in which ultrasound is used
to examine the heart. The equipment is far superior
to that used by fishermen. In addition to providing
single-dimension images, known as M-mode echo that allows
accurate measurement of the heart chambers, the echocardiogram
also offers far more sophisticated and advanced imaging.
This is known as two- dimensional (2-D) Echo and is
capable of displaying a cross-sectional "slice"
of the beating heart, including the chambers, valves
and the major blood vessels that exit from the left
and right ventricle
An echocardiogram can be obtained
in a physician's office or in the hospital. For a resting
echocardiogram (in contrast to a stress echo or TEE,
discussed elsewhere) no special preparation is necessary.
Clothing from the upper body is removed and covered
by a gown or sheet to keep you comfortable and maintain
the privacy of females. The patient then lies on an
examination table or a hospital bed
Sticky patches or electrodes are attached
to the chest and shoulders and connected to electrodes
or wires. These help to record the electrocardiogram
(EKG or ECG) during the echocardiography test. The EKG
helps in the timing of various cardiac events (filling
and emptying of chambers). A colorless gel is then applied
to the chest and the echo transducer is placed on top
of it. The echo technologist then makes recordings from
different parts of the chest to obtain several views
of the heart. You may be asked to move form your back
and to the side. Instructions may also be given for
you to breathe slowly or to hold your breath. This helps
in obtaining higher quality pictures. The images are
constantly viewed on the monitor. It is also recorded
on photographic paper and on videotape. The tape offers
a permanent record of the examination and is reviewed
by the physician prior to completion of the final report.
What is a Doppler Examination?
Doppler is a special part of the ultrasound examination
that assess blood flow (direction and velocity). In
contrast, the M-mode and 2-D Echo evaluates the size,
thickness and movement of heart structures (chambers,
valves, etc.). During the Doppler examination, the ultrasound
beams will evaluate the flow of blood as it makes it
way though and out of the heart. This information is
presented visually on the monitor (as color images or
grayscale tracings and also as a series of audible signals
with a swishing or pulsating sound)..
What information does Echocardiography
and Doppler provide?
Echocardiography is an invaluable tool in providing
the doctor with important information about the following:
Size of the chambers
of the heart, including the dimension or volume of the
cavity and the thickness of the walls. The appearance
of the walls may also help identify certain types of
heart disease that predominantly involve the heart muscle.
In patients with long standing hypertension or high
blood pressure, the test can determine the thickness
and "stiffness" of the LV walls. When the
LV pump function is reduced in patients with heart failure,
the LV and RV tends to dilate or enlarge. Echocardiography
can measure the severity of this enlargement. Serial
studies performed on an annual basis can gauge the response
of the heart can be assessed by echocardiography. One
can tell if the pumping power of the heart is normal
or reduced to a mild or severe degree. This measure
is known as an ejection fraction or EF. A normal EF
is around 55 to 65%. Numbers below 45% usually represent
some decrease in the pumping strength of the heart,
while numbers below 30 to 35% are representative of
an important decrease.
also identify if the heart is pumping poorly due to
a condition known as cardiomyopathy (pronounced cardio-myo-puth-e),
or if one or more isolated areas have depressed movement
(due to prior heart attacks). Thus, echocardiography
can assess the pumping ability of each chamber of the
heart and also the movement of each visualized wall.
The decreased movement, in turn, can be graded from
mild to severe. In extreme cases, an area affected by
a heart attack may have no movement (akinesia, pronounced
a-kine-neez-ya), or may even bulge in the opposite direction
(dyskinesia, pronounced dis-kine-neez-ya). The latter
is seen in patients with aneurysm (pronounced an-new-riz-um
) of the left ventricle or LV. It must be remembered
that LV aneurysm due to an old heart attack does not
usually rupture or "burst."
The top diagram on
the monitor shows an ultrasound beam (gray triangular
area) traveling through the right (RV) and left (LV)
ventricle. You can also see the aorta (Ao), left atrium
(LA), aortic valve (AV) and mitral valve (MV). Please
note that you can review cardiac anatomy and physiology
by clicking here. The two pictures on the bottom of
the monitor were taken from actual patients. The arrows
point to the septum or partition between the RV and
LV. The lower left picture demonstrates normal movement
of the septum as it moves towards the opposite wall
of the LV when the heart contracts. In contrast, the
patient on the bottom right has had a heart attack involving
the septum. Note that the septum moves sluggishly. Also,
it is thinner and "shriveled" as a result
of the heart attack.
Valve Function: Echocardiography
identifies the structure, thickness and movement of
each heart valve. It can help determine if the valve
is normal, scarred from an infection or rheumatic fever,
thickened, calcified (loaded with calcium), torn, etc.
It can also assess the function of prosthetic or artificial
The additional use of Doppler helps to identify abnormal
leakage across heart valves and determine their severity.
Doppler is also very useful in diagnosing the presence
and severity of valve stenosis (pronounced stee-no-sis)
or narrowing. Remember, unlike echocardiography, Doppler
follows the direction and velocity of blood flow rather
than the movement of the valve leaflets or components.
Thus, reversed blood direction is seen with leakages
while increased forward velocity of flow with a characteristic
pattern is noted with valve stenosis.
Echocardiography is used to diagnose mitral valve prolapse
(MVP), while Doppler identifies whether it is associated
with leakage or regurgitation of the mitral valve (MR).
The presence of MR frequently prompts the use of antibiotics
prior to any dental or non-sterile surgical procedure.
Such action helps reduce the rare complication of valve
Low blood pressure can occur in the setting of poor
heart function but may also be seen when patient's have
a reduced volume of circulating blood (as seen with
dehydration, blood loss, use of diuretics or "water
pill.", etc.). In many cases, the diagnosis can
be made on the basis of history, physical examination
and blood tests. However, confusion may be caused when
patients have a combination of problems. Echocardiography
may help clarify the confusion. The inferior vena cava
(the major vein that returns blood from the lower half
of the body to the right atrium) is distended or increased
in size in patients with heart failure and reduced in
caliber when the blood volume is reduced.
Other Uses: Echocardiography
is useful in the diagnosis of fluid in the pericardium
(the sac that surrounds the heart). It also determines
when the problem is severe and potentially life-threatening.
Other diagnoses (plural for diagnosis) made by Doppler
or echocardiography include congenital heart diseases,
blood clots or tumors within the heart, active infection
of the heart valves, abnormal elevation of pressure
within the lungs, etc.
How safe is echocardiography?
Echocardiography is extremely safe. There are no known
risks from the clinical use of ultrasound during this
type of testing.
How long does it take?
A brief examination in an uncomplicated case may be
done within 15 to 20 minutes. The additional use of
Doppler may add an additional 10 to 20 minutes. However,
it may take up to an hour when there are multiple problems
or when there are technical problems (for example, patients
with lung disease, obesity, restlessness, and significant
shortness of breath may be more difficult to image).
When can I expect to
receive the results? If a doctor is present
during the test or reviews it while you are still in
the office, you may be able to get the results before
you leave. However, the doctor is not routinely present
during the test and you may have to wait from one to
several days before the images have been reviewed by
a physician and the results are sent to you by phone
or mail. Some physicians will discuss your case before
the study is performed and will contact you if there
are significant unexpected findings. For example, if
you are expected to have a finding or known to have
a given disease, your physician may indicate that he
or she will call you only if there are significant unexpected
findings. You may also be contacted if echocardiography
reveals a finding that influences a change in treatment.
For example, the presence of a distended inferior vena
cava (discussed above) may result in increasing the
dose of your diuretic or water pill, if it is indicated
by other aspects of your condition.
If you are anxious or confused about the results feel
free to contact the physician's office staff. They can
usually clarify a question for you.