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Types of Acyanotic Heart Disease Patent
Ductus Arteriosus (PDA)
In PDA, or patent ductus arteriosus, is a persistent
connection between the aorta and the pulmonary artery. The PDA is a normal connection
when the baby was still in the uterus. When the baby is in the uterus, it depends
on the PDA to get oxygen from the mother. When the baby is born, there are hormonal
changes in the baby that normally close off the PDA, since the baby is now breathing,
and no longer needs the PDA. A PDA defect is when this ductus doesn't close as
it normally should. Persistence of the PDA may cause an excessive amount of blood
to go to the lungs. Depending on the size of the
PDA and the condition on the lung, the baby may have no symptoms, or may have
severe heart failure.
PDAs
should be closed because there is a real risk of endocarditis, or a heart infection,
over the course of a lifetime. PDA's are often closed in the cardiac catheterization
laboratory, by the insertion of specially designed coils. These coils sit in the
PDA, and expand to the point where they prevent all of the blood flow. The traditional
way of closing a ductus is through an operation and closure under direct vision,
although this method is now typically reserved for premature neonates and if an
interventional cardiac catheterization laboratory is not readily available. Closure
of a PDA by either interventional cardiac catheterization or surgery is safe and
carries negligible morbidity and mortality. The
risk of Patent ductus arteriosus risk is also increases at higher altitude because
of the lower concentration of oxygen. Coarctation
of the Aorta The aorta is
the main artery that sends oxygen rich blood from the heart to the body. Coarctation
of the aorta is a constricted segment of the aorta that obstructs blood flow to
the body. The left ventricle has to pump harder because the pressure
is high. Because of this, the heart may enlarge. Coarctations typically occur
as isolated defects, but may occur with a ventricular septal defect, subaortic
stenosis, or complex congenital heart defects. Surgery may be needed to correct
the defect, depending on the severity of the coarctation and the presence of other
congenital defects. Another option may be a balloon angioplasty. This procedure
is done in the cardiac catheterization lab. Your physician should discuss the
various options for your child. Atrial
Septal Defect (ASD) The
septum of the heart separates the right and left sides of the heart. A hole in
the wall between the two upper chambers is called an atrial septal defect, or
ASD. This is one of the simplest forms of congenital heart disease, and was one
of the congenital heart defects to be repaired surgically. Normally, blood entering
the right side of the heart stays on the right side (this is low oxygen blood),
and blood on the left side of the heart stays on the left side (this is oxygen
rich blood) which is then pumped to the body. When a defect or "hole" is present
between the atria (or upper chambers), some oxygen rich blood leaks back to the
right side of the heart. It then goes back to the lungs even though it is already
rich in oxygen. Because of this, there is a significant increase in the blood
that goes to the lungs. Over the course of several years, this may impair the
function of both the heart and the lungs, resulting in a markedly foreshortened
life expectancy. This defect is usually corrected with open heart surgery to restore
normal blood circulation. Atrial
septal defect
is the 5th most common Congenital Heart Disease. Ventriuclar
Septal Defect (VSD) A ventricular
septal defect, or VSD, is the most common kind of congenital heart defect.
This is what many people refer to as a "hole in the heart". The septum is the
wall that separates the right and left sides of the heart. A hole in the wall
between the two lower chambers is called a ventricular septal defect, or VSD for
short. Normally, blood entering the
right side of the heart stays on the right side (this is low oxygen blood), and
blood on the left side of the heart stays on the left side (this is oxygen rich
blood) which is then pumped to the rest of the body. When a defect or "hole" is
present between the ventricles (or lower chambers), blood from the left side of
the heart is forced through the defect to the right side every time the heart
beats. It then goes back to the lungs even though it is already rich in oxygen.
Because of this, blood that is not yet oxygen rich can’t get to the lungs. The
most common signs and symptoms are trouble eating and gaining weight, breathlessness
and easy fatigability. A baby with a large VSD tires quickly after not eating
very much, falls asleep, wakes us in a short while quite hungry, tries to eat
again, tires easily. This cycle is repeated.
Because the heart has to pump extra blood, it may enlarge. Also, because there’s
more blood going to the lungs, high pressure may occur in the blood vessels there.
This may cause permanent damage to the walls of the blood vessels over time. Many,
if not most, of all VSDs will close on their own. Those that close on their own
are usually small and do so in the first year of life. Large VSDs, especially
those that don't close in the first year of life, will usually need to be closed
surgically. VSD closure is one of the most commonly performed congenital heart
operations, and is a safe and effective operation. The child would be expected
to have virtually normal growth, development, and life expectancy following repair. Premature
infants are 10 times more likely to have this defect
than full term infants.
Atrioventricular
Septal Defect (AVSD) This
defect is best described as a large hole in the middle of the heart. It results
from a lack of separation of the atria and the ventricles into separate chambers,
and a lack of separation of the mitral and tricuspid valves into two separate
valves. Therefore there is a large connection between the two atria, between the
two ventricles, and a single atrioventricular (or AV) valve, whereas there should
be separate mitral and tricuspid valves. A very complex defect indeed! The defect
is named an atrioventricular septal defect, or AVSD. An old name for this defect
is an atrioventricular canal defect, or AV canal for short. In it’s simplest form,
there is only an atrial septal defect, and this this is treated just like an ASD.
More complex forms of AVSD also include
the opening between the two ventricles, along with the lack of separation of the
AV valve into separate mitral and tricuspid valves. In the most complex form,
not only are there defects between the atria, the ventricles, and the mitral/tricuspid
valves, one of the ventricles may not be properly formed, the valves may be 'over-riding'
or 'straddling', there may be obstruction to the aorta, and other things. The
reason this defect may be so complex is that it probably occurs during the very
first stages of fetal development. The large hole in the center of the heart lets
blood from the left side of the heart (this is oxygen rich blood) pass into the
right side of the heart. It then goes back to the lungs even though it has already
been oxygenated. Because of the large amount of extra blood going to the lungs,
high blood pressure may occur there and over time can damage the blood vessels.
Additionally, the valve between the upper (atrial) and lower (ventricular) chambers
does not close properly. Blood then leaks backward from the ventricular chambers
to the atrial chambers. This leak is referred to as an insufficiency of the valve.
When the valve leaks, the heart has to pump more blood. This can lead to many
other problems, including enlargement of the heart. This defect is usually corrected
in infancy with open heart surgery to restore normal blood circulation through
the heart. Surgical repair consists of separation of the common AV valve into
two valves, along with closure of the VSD and ASD. The operation represents a
surgical separation of the valves, ventricles and atria, so it tends to be a big
operation. Some children, however, may have too complex a defect to correct in
infancy, and would initially require a pulmonary artery banding. This will decrease
blood flow and reduce the high pressure in the lungs. When the child is older,
the band will be removed and the defect corrected with open heart surgery. Sixty-nine
per cent (69%) of all AV canal patients have Down syndrome. Aortic
Stenosis (AS) Stenosis means
narrowing. Aortic stenosis is then a narrowing of the aortic valve or a narrowing
of the aorta directly above (supravalvar) or below (subvalvar) the aortic valve.
Normally, oxygen rich blood is pumped from the left ventricle, through the aortic
valve and into the aorta. The aorta is the main artery that sends oxygen rich
blood to the body. When aortic stenosis, it makes it very hard for the heart to
pump blood to the body. Depending on the severity of the stenosis, open heart
surgery may be needed to correct the defect. Another option may be a balloon valvuloplasty.
This procedure is done in the cardiac catheterization lab. Your physician should
offer you the best option for your child. Pulmonary
Stenosis (PS) Stenosis means
narrowing. Pulmonary stenosis is then a narrowing of the pulmonary valve. Normally
the pulmonary valve opens to let low oxygen blood flow from the right ventricle
to the lungs where the blood is oxygenated. Because of the narrowing the right
ventricle has to pump harder to get past the stenotic valve. This can sometimes
lead to enlargement of the right ventricle. Depending on the severity of the pulmonary
stenosis, open heart surgery may be indicated to correct the defect. Another option
may be a balloon valvuloplasty. This procedure is done in the cardiac catheterization
lab. Your doctor should offer you the best option for your child. Some of these
defects can be corrected by surgical treatment. Fortunately, surgical treatment
is often possible a week after the child is born and full recovery is possible.
Other causes of congenital heart defects
are the occurrence of rubella (German measles) in a woman during the first three
months of pregnancy and intake of and a number of drugs, including anti-epileptic
agents by a woman while during the pregnancy. These heart defects can be diagnosed
through prenatal ultrasonography and amniocentesis. Pulmonary
stenosis is the second most common congenital heart disease.
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