Congenital Heart Disease
According to the American Heart Association, about 9 of every 1,000 babies born in
the U.S. have a congenital heart defect. This is a problem that occurs as the baby's
heart is developing during pregnancy, before the baby is born. Congenital heart defects
are the most common birth defects.
A baby's heart starts to develop at conception, but is completely formed by 8 weeks
into the pregnancy. Congenital heart defects happen during this important first 8
weeks of the baby's development. Specific steps must take place for the heart to form
correctly. Often, congenital heart defects are a result of one of these steps not
happening at the right time. For example, a hole is left where a dividing wall should
have formed, or a single blood vessel is left, where 2 should have been.
What causes congenital heart disease?
Most congenital heart defects have no known cause. Mothers will often wonder if something
they did during the pregnancy caused the heart problem. In most cases, no specific
cause can be found. Some heart problems do occur more often in families, so there
may be a genetic link to some heart defects. Some heart problems are likely to occur
if the mother had a disease while pregnant and was taking medicines, such as antiseizure
medicines or the acne medicine isotretinoin. But, most of the time, there is no clear
reason for the heart defect
Congenital heart problems range from simple to complex. Some heart problems can be
watched by the baby's doctor and managed with medicines. Others will require surgery,
sometimes as soon as in the first few hours after birth. A baby may even "grow out"
of some of the simpler heart problems, such as patent ductus arteriosus or atrial
septal defect. These defects may simply close up on their own with growth. Other babies
will have a combination of defects and require several operations throughout their
What are the different types of congenital heart defects?
Experts classify congenital heart defects into several categories to better understand
the problems the baby will experience. They include:
Problems that cause too much blood to pass through the lungs. These defects allow
oxygen-rich blood that should be traveling to the body to recirculate through the
lungs, causing increased pressure and stress in the lungs.
Problems that cause too little blood to pass through the lungs. These defects allow
blood that has not been to the lungs to pick up oxygen (and, therefore, is oxygen-poor)
to travel to the body. The body does not get enough oxygen with these heart problems,
and the baby may be cyanotic, or have a blue coloring.
Problems that cause too little blood to travel to the body. These defects are a result
of underdeveloped chambers of the heart or blockages in blood vessels that prevent
the proper amount of blood from traveling to the body to meet its needs.
Again, in some cases there will be a mix of several heart defects. This creates a
more complex problem that can fall into several of these categories.
Some of the problems that cause too much blood to pass through the lungs include the
Patent ductus arteriosus (PDA). This defect occurs when the normal closure of the
ductus arteriosus, which is present in all fetuses, does not occur. Extra blood goes
from the aorta into the lungs and may lead to "flooding" of the lungs, rapid breathing,
and poor weight gain. PDA is often seen in premature infants.
Atrial septal defect (ASD). In this condition, there is a hole between the 2 upper
chambers of the heart—the right and left atria. This causes an abnormal blood flow
through the heart. Some children may have no symptoms and appear healthy. However,
if the ASD is large, permitting a large amount of blood to pass to the right side,
symptoms will be noted.
Ventricular septal defect (VSD). In this condition, a hole in the ventricular septum
(a dividing wall between the 2 lower chambers of the heart— the right and left ventricles)
occurs. Because of this opening, blood from the left ventricle flows back into the
right ventricle, due to higher pressure in the left ventricle. This causes an extra
volume of blood to be pumped into the lungs by the right ventricle, which can create
congestion in the lungs.
Atrioventricular canal (AVC or AV canal). AVC is a heart problem that involves several
abnormalities of structures inside the heart. These include atrial septal defect,
ventricular septal defect, and improperly formed mitral and/or tricuspid valves.
Some of the problems that cause too little blood to pass through the lungs include
Tricuspid atresia. In this condition, the tricuspid valve does not form. Therefore,
no blood flows from the right atrium to the right ventricle. Tricuspid atresia is
characterized by the following:
A series of surgical procedures are often needed to increase the blood flow to the
lungs and establish separate circulations.
Pulmonary atresia. A congenital defect in which the pulmonary valve or artery are
underdeveloped. Normally, the pulmonary valve is found between the right ventricle
and the pulmonary artery. It has 3 leaflets that function like a one-way door, allowing
blood to flow forward into the pulmonary artery, but not backward into the right ventricle.
With pulmonary atresia, problems with valve development prevent the leaflets from
opening, therefore, blood cannot flow forward from the right ventricle to the lungs.
Transposition of the great arteries. With this congenital heart defect, the positions
of the pulmonary artery and the aorta are reversed, thus:
The aorta originates from the right ventricle, so most of the oxygen-poor blood returning
to the heart from the body is pumped back out without first going to the lungs.
The pulmonary artery originates from the left ventricle, so that most of the oxygen-rich
blood returning from the lungs goes back to the lungs again
Double outlet right ventricle (DORV). A complex form of congenital heart defect, in
which both the aorta and the pulmonary artery are connected to the right ventricle.
Truncus arteriosus. During normal fetal development, the aorta and pulmonary artery
start as a single blood vessel, and then the vessel divides into 2 separate arteries.
Truncus arteriosus occurs when the single great vessel fails to separate completely.
This leaves a large connection between the aorta and the pulmonary artery.
Some of the problems that cause too little blood to travel to the body include the
Coarctation of the aorta (CoA). In this condition, the aorta is narrowed or constricted.
This obstructs blood flow to the lower part of the body and increases blood pressure
above the constriction. Usually there are no symptoms at birth, but they can develop
as early as the first week of life. If severe symptoms of high blood pressure and
congestive heart failure develop, surgery may be considered.
Aortic stenosis (AS). In AS, the aortic valve between the left ventricle and the aorta
did not form properly and is narrowed. This makes it difficult for the heart to pump
blood to the body. A normal valve has 3 leaflets or cusps, but a stenotic valve may
have only 1 cusp (unicuspid) or 2 cusps (bicuspid).
Although aortic stenosis may not cause symptoms, it may worsen over time. Surgery
or a catheterization procedure may be needed to correct the blockage, or the valve
may need to be replaced with an artificial one.
A complex combination of heart defects known as hypoplastic left heart syndrome can
Hypoplastic left heart syndrome (HLHS). A combination of several abnormalities of
the heart and the great blood vessels. In HLHS, most of the structures on the left
side of the heart (including the left ventricle, mitral valve, aorta, and aortic valve)
are small and underdeveloped. The degree of underdevelopment differs from child to
child. The left ventricle may not be able to pump enough blood to the body. HLHS is
fatal without treatment.
Who treats congenital heart defects?
Babies with congenital heart problems are followed by specialists called pediatric
cardiologists. These doctors diagnose heart defects and help manage the health of
children before and after surgical repair of the heart problem. Specialists who correct
heart problems in the operating room are known as pediatric cardiovascular, or cardiothoracic
A new subspecialty within cardiology is emerging, as the number of adults with congenital
heart disease (CHD) is now greater than the number of babies born with CHD. This improved
survival is a result of advances in diagnostic procedures and treatment interventions.
To achieve and maintain the highest possible level of wellness, it is imperative that
anyone born with CHD, who has reached adulthood, transition to the appropriate type
of cardiac care. The type of care required is based on the type of CHD a person has.
Those with simple CHD can generally be cared for by a community adult cardiologist.
Those with more complex types of CHD will need to be cared for at a center that specializes
in adult CHD.
For adults with CHD, guidance is necessary for planning key life issues, such as college,
career, employment, insurance, activity, lifestyle, inheritance, family planning,
pregnancy, chronic care, disability, and end of life. Knowledge about specific congenital
heart conditions, and expectations for long-term outcomes and potential complications
and risks, must be reviewed as part of the successful transition from pediatric care
to adult care. Parents should help pass on the responsibility for this knowledge,
and accountability for ongoing care to their young adult children. This will help
ensure the transition to adult specialty care and will optimize the health status
of the young adult with CHD.