Ventricular
Septal Defect (VSD)
A ventricular
septal defect is an opening in the ventricular
septum, or dividing wall between the two lower
chambers of the heart known as the right and left
ventricles. VSD is a congenital (present at birth)
heart defect. As the fetus is growing, something
occurs to affect heart development during the
first 8 weeks of pregnancy, resulting in a VSD.
Normally,
oxygen-poor (blue) blood returns to the right
atrium from the body, travels to the right ventricle,
then is pumped into the lungs where it receives
oxygen. Oxygen-rich (red) blood returns to the
left atrium from the lungs, passes into the left
ventricle, and then is pumped out to the body
through the aorta.
A ventricular
septal defect allows oxygen-rich (red) blood to
pass from the left ventricle, through the opening
in the septum, and then mix with oxygen-poor (blue)
blood in the right ventricle.
Two
basic types of VSD include the following:
- perimembranous VSD
- an opening in the upper section of the ventricular
septum, near the valves, occurs in 75 percent
of all VSD cases.
- muscular VSD - an opening
in the lower section of the ventricular septum
occurs in up to 20 percent of all VSD cases.
Ventricular
septal defects are the most commonly occurring
type of congenital heart defect, occurring in
14 to 17 percent of babies born each year.
The
heart is forming during the first 8 weeks of fetal
development. It begins as a hollow tube, then
partitions within the tube develop that eventually
become the septa (or walls) dividing the right
side of the heart from the left. Ventricular septal
defects occur when the partitioning process does
not occur completely, leaving an opening in the
ventricular septum.
Some
congenital heart defects may have a genetic link,
either occurring due to a defect in a gene, a
chromosome abnormality, or environmental exposure,
causing heart problems to occur more often in
certain families. Most ventricular septal defects
occur sporadically (by chance), with no clear
reason for their development.
If not
treated, this heart defect can cause lung disease.
When blood passes through the VSD from the left
ventricle to the right ventricle, a larger volume
of blood than normal must be handled by the right
side of the heart. Extra blood then passes through
the pulmonary artery into the lungs, causing higher
pressure than normal in the blood vessels in the
lungs.
A small
opening in the ventricular septum allows a small
amount of blood to pass through from the left
ventricle to the right ventricle. A large opening
allows more blood to pass through and mix with
the normal blood flow in the right heart. Extra
blood causes higher pressure in the blood vessels
in the lungs. The larger the volume of blood that
goes to the lungs, the higher the pressure.
The
lungs are able to cope with this extra pressure
for while, depending on exactly how high the pressure
is. After a while, however, the blood vessels
in the lungs become diseased by the extra pressure.
As pressure
builds up in the lungs, the flow of blood from
the left ventricle, through the VSD, into the
right ventricle, and on to the lungs will diminish.
This helps preserve the function of the lungs,
but causes yet another problem. Blood flow within
the heart goes from areas where the pressure is
high to areas where the pressure is low. If a
ventricular septal defect is not repaired, and
lung disease begins to occur, pressure in the
right side of the heart will eventually exceed
pressure in the left. In this instance, it will
be easier for oxygen-poor (blue) blood to flow
from the right ventricle, through the VSD, into
the left ventricle, and on to the body. When this
happens, the body does not receive enough oxygen
in the bloodstream to meet its needs.
Because
blood is pumped at high pressure by the left ventricle
through the VSD, tissue damage may eventually
occur in the right ventricle. Bacteria in the
bloodstream can easily infect this injured area,
causing a serious illness known as bacterial endocarditis.
Some
ventricular septal defects are found in combination
with other heart defects (such as in transposition
of the great arteries).
The
size of the ventricular septal opening will affect
the type of symptoms noted, the severity of symptoms,
and the age at which they first occur. A VSD permits
extra blood to pass from the left ventricle through
to the right side of the heart, and the right
ventricle and lungs become overworked as a result.
The larger the opening, the greater the amount
of blood that passes through and overloads the
right ventricle and lungs.
Symptoms
often occur in infancy. The following are the
most common symptoms of VSD. However, each child
may experience symptoms differently. Symptoms
may include:
- fatigue
- sweating
- rapid breathing
- heavy breathing
- congested breathing
- disinterest in feeding,
or tiring while feeding
- poor weight gain
The
symptoms of VSD may resemble other medical conditions
or heart problems. Always consult your child's
physician for a diagnosis.
Your
child's physician may have heard a heart murmur
during a physical examination, and referred your
child to a pediatric cardiologist for a diagnosis.
A heart murmur is simply a noise caused by the
turbulence of blood flowing through the opening
from the left side of the heart to the right.
A pediatric
cardiologist specializes in the diagnosis and
medical management of congenital heart defects,
as well as heart problems that may develop later
in childhood. The cardiologist will perform a
physical examination, listening to the heart and
lungs, and make other observations that help in
the diagnosis. The location within the chest where
the murmur is heard best, as well as the loudness
and quality of the murmur (harsh, blowing, etc.)
will give the cardiologist an initial idea of
which heart problem your child may have. However,
other tests are needed to help with the diagnosis,
and may include the following:
- chest x-ray -
a diagnostic test which uses invisible electromagnetic
energy beams to produce images of internal tissues,
bones, and organs onto film. With a VSD, the
heart may be enlarged because the right ventricle
handles larger amounts of blood flow than normal.
Also, there may be changes that take place in
the lungs due to extra blood flow that can be
seen on an x-ray.
- electrocardiogram
(ECG or EKG) - a test that records
the electrical activity of the heart, shows
abnormal rhythms (arrhythmias or dysrhythmias),
and detects heart muscle stress.
- echocardiogram (echo)
- a procedure that evaluates the
structure and function of the heart by using
sound waves recorded on an electronic sensor
that produce a moving picture of the heart and
heart valves. An echo can show the pattern of
blood flow through the septal opening, and determine
how large the opening is, as well as much blood
is passing through it.
- cardiac catheterization
- a cardiac catheterization is an
invasive procedure that gives very detailed
information about the structures inside the
heart. Under sedation, a small, thin, flexible
tube (catheter) is inserted into a blood vessel
in the groin, and guided to the inside of the
heart. Blood pressure and oxygen measurements
are taken in the four chambers of the heart,
as well as the pulmonary artery and aorta. Contrast
dye is also injected to more clearly visualize
the structures inside the heart.
Specific
treatment for VSD will be determined by your child's
physician based on:
- your child's age, overall
health, and medical history
- extent of the disease
- your child's tolerance
for specific medications, procedures, or therapies
- expectations for the
course of the disease
- your opinion or preference
Small
ventricular septal defects may close spontaneously
as your child grows. A larger VSD usually requires
surgical repair. Regardless of the type, once
a ventricular septal defect is diagnosed, your
child's cardiologist will evaluate your child
periodically to see whether it is closing on its
own. A VSD will be repaired if it has not closed
on its own - to prevent lung problems that will
develop from long-time exposure to extra blood
flow. Treatment may include:
In most
cases, children will spend time in the intensive
care unit (ICU) after an VSD repair. During the
first several hours after surgery, your child
will most likely be drowsy from the anesthesia
that was used during the operation, and from medications
given to relax him/her and to help with pain.
As time goes by, your child will become more alert.
While
your child is in the ICU, special equipment will
be used to help him/her recover, and may include
the following:
- ventilator -
a machine that helps your child breathe while
he/she is under anesthesia during the operation.
A small, plastic tube is guided into the windpipe
and attached to the ventilator, which breathes
for your child while he/she is too sleepy to
breathe effectively on his/her own. Many children
have the ventilator tube removed right after
surgery, but some other children will benefit
from remaining on the ventilator for a few hours
afterwards so they can rest.
- intravenous (IV) catheters
- small, plastic tubes inserted
through the skin into blood vessels to provide
IV fluids and important medications that help
your child recover from the operation.
- arterial line -
a specialized IV placed in the wrist, or other
area of the body where a pulse can be felt,
that measures blood pressure continuously during
surgery and while your child is in the ICU.
- nasogastric (NG) tube
- a small, flexible tube that keeps
the stomach drained of acid and gas bubbles
that may build up during surgery.
- urinary catheter -
a small, flexible tube that allows urine to
drain out of the bladder and accurately measures
how much urine the body makes, which helps determine
how well the heart is functioning. After surgery,
the heart will be a little weaker than it was
before, and, therefore, the body may start to
hold onto fluid, causing swelling and puffiness.
Diuretics may be given to help the kidneys to
remove excess fluids from the body.
- chest tube -
a drainage tube may be inserted to keep the
chest free of blood that would otherwise accumulate
after the incision is closed. Bleeding may occur
for several hours, or even a few days after
surgery.
- heart monitor -
a machine that constantly displays a picture
of your child's heart rhythm, and monitors heart
rate, arterial blood pressure, and other values.
Your
child may need other equipment not mentioned here
to provide support while in the ICU, or afterwards.
The hospital staff will explain all of the necessary
equipment to you.
Your
child will be kept as comfortable as possible
with several different medications; some which
relieve pain, and some which relieve anxiety.
The staff may also ask for your input as to how
best to soothe and comfort your child.
After
discharged from the ICU, your child will recuperate
on another hospital unit for a few days before
going home. You will learn how to care for your
child at home before your child is discharged.
Your child may need to take medications for a
while, and these will be explained to you. The
staff will give you written instructions regarding
medications, activity limitations, and follow-up
appointments before your child is discharged.
Most
infants and older children feel fairly comfortable
when they go home. Pain medications, such as acetaminophen
or ibuprofen, may be recommended to keep your
child comfortable. Your child's physician will
discuss pain control before your child is discharged
from the hospital.
Often,
infants who fed poorly prior to surgery have more
energy after the recuperation period, and begin
to eat better and gain weight faster.
After
surgery, older children usually have a fair tolerance
for activity. Your child may become tired quicker
than before surgery, but usually will be allowed
to play with supervision, while avoiding blows
to the chest that might cause injury to the incision
or breastbone. Within a few weeks, your child
should be fully recovered and able to participate
in normal activity.
You
may receive additional instructions from your
child's physicians and the hospital staff.
Most
children who have had a ventricular septal defect
repair will live healthy lives. Activity levels,
appetite, and growth will return to normal in
most children. Your child's cardiologist may recommend
that antibiotics be given to prevent bacterial
endocarditis for a specific time period after
discharge from the hospital.
Outcomes
also depend on the type of VSD, as well as how
early in life the VSD was diagnosed and whether
or not it was repaired. With early diagnosis and
repair of a VSD, the outcome is generally excellent,
and minimal follow-up is necessary. When a VSD
is diagnosed later in life, if complications occur
after surgical closure, or the VSD is never repaired,
the outlook is generally poor. There is a risk
for developing pulmonary hypertension (high blood
pressure in the blood vessels of the lungs) or
Eisenmenger’s syndrome. These individuals
should receive follow-up care at a center that
specializes in congenital heart disease.
Consult
your child's physician regarding the specific
outlook for your child.
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