CONGENITAL CARDIOVASCULAR DISEASE
What is congenital cardiovascular disease or congenital heart disease?
Congenital means inborn or existing at birth. Among the terms you may hear are congenital heart defect, congenital heart disease and congenital cardiovascular disease. The word "defect" is more accurate than "disease." A congenital cardiovascular defect occurs when the heart or blood vessels near the heart don't develop normally before birth.
What causes congenital cardiovascular
defects?
Congenital cardiovascular defects are present in about one percent of live births. They're the most common congenital malformations in newborns. In most cases scientists don't know why they occur. Sometimes a viral infection causes serious problems. German measles (also called rubella) is an example. If a woman contracts German measles while pregnant, it can interfere with how her baby's heart develops or produce other malformations. Other viral diseases also may cause congenital defects.
Heredity sometimes plays a role in congenital cardiovascular disease. More than one child in a family may have a congenital cardiovascular defect, but this rarely occurs. Certain conditions affecting multiple organs, such as Down's syndrome, can involve the heart, too. Some prescription drugs and over-the-counter medicines, as well as alcohol and "street" drugs, may increase the risk of having a baby with a heart defect.
Other factors that affect the heart's development are under study. The fact is, we don't know what causes most congenital cardiovascular defects.
What are the types of congenital defects?
Most heart defects either 1) obstruct blood flow in the heart or vessels near it or 2) cause blood to flow through the heart in an abnormal pattern. Rarely defects occur in which only one ventricle (single ventricle) is present, or both the pulmonary artery and aorta arise from the same ventricle (double outlet ventricle). A third rare defect occurs when the right or left side of the heart is incompletely formed - hypoplastic heart.
The following defects are described in this section: (For more information on children and heart disease, see the AHA Website, www.americanheart.org/children/index.html. For information on congenital defects in Spanish, see the Web site, www.americanheart.org/Spanish/index.html)
Atrioventricular
(A-V) canal defect Hypoplastic
left heart syndrome Total
anomalous pulmonary venous (P-V) connection
Patent ductus arteriosus (P.D.A.)
This defect allows blood to mix between the pulmonary artery and the aorta . Before birth there's an open passageway (the ductus arteriosus) between these two blood vessels. Normally this closes within a few hours of birth. When this doesn't happen, some blood that should flow through the aorta and on to nourish the body returns to the lungs. A ductus that doesn't close is quite common in premature infants but rather rare in full-term babies.
If the ductus arteriosus is large, a child may tire quickly, grow slowly, catch pneumonia easily and breathe rapidly. In some children symptoms may not occur until after the first weeks or months of life. If the ductus arteriosus is small, the child seems well. If surgery is needed, the surgeon can close the ductus arteriosus by tying it, without opening the heart. If there's no other defect, this restores the circulation to normal.
Obstruction defects
An obstruction is a narrowing that partly or completely blocks the flow of blood. Obstructions called stenoses can occur in heart valves, arteries or veins.
The three most common forms of obstructed blood flow are pulmonary stenosis, aortic stenosis and coarctation of the aorta. Related but less common forms include bicuspid aortic valve, subaortic stenosis and Ebstein's anomaly.
-
The pulmonary or pulmonic
valve is between the right ventricle
and the pulmonary artery
. It opens to allow blood to flow from the right ventricle to the lungs. A
defective pulmonary valve that doesn't open properly is called stenotic
. That means the right ventricle must pump harder than normal to overcome
the obstruction.
If the stenosis is severe, especially in babies, some cyanosis (blueness) may occur. Older children usually have no symptoms. Treatment is needed when the pressure in the right ventricle is higher than normal. In most children the obstruction can be relieved by a procedure called balloon valvuloplasty . In other patients, open-heart surgery may be needed. During surgery, the valve can usually be opened satisfactorily. The outlook after balloon valvuloplasty or surgery is favorable, but follow-up is required to determine if heart function returns to normal.
People with pulmonary stenosis, before and after treatment, are at risk for getting an infection of the valve (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
Sometimes
stenosis is severe and symptoms occur in infancy. Otherwise, most children
with aortic stenosis have no symptoms. In some children, chest pain, unusual
tiring, dizziness or fainting may occur. The need for surgery depends on how
bad the stenosis is. In children, a surgeon may be able to enlarge the valve
opening. Surgery may improve the stenosis, but the valve remains deformed.
Eventually the valve may need to be replaced with an artificial one.
A procedure called balloon valvuloplasty has been used in some children with aortic stenosis. The long-term results of this procedure are still being studied. Children with aortic stenosis need lifelong medical follow-up. Even mild stenosis may worsen over time, and surgical relief of a blockage is sometimes incomplete. Check with your pediatric cardiologist about limiting some kinds of exercise.
People with aortic stenosis, before and after treatment, are at risk for getting an infection of the valve (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
- The aorta is pinched 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 after birth. A baby may develop congestive
heart failure or high blood pressure that requires early surgery. Otherwise,
surgery usually can be delayed. A child with a severe coarctation should
have surgery in early childhood. This prevents problems such as developing
high blood pressure as an adult.
The outlook after surgery is favorable, but long-term follow-up is required. Rarely, coarctation of the aorta may recur. Some of these cases can be treated by balloon angioplasty . The long-term results of this procedure are still being studied. Also, blood pressure may stay high even when the aorta's narrowing has been repaired.
People with coarctation of the aorta, before and after treatment, are at risk for getting an infection within the aorta or the heart valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
People with bicuspid aortic valve, before and after treatment, are at risk for getting an infection within the aorta or the heart valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
People with subaortic stenosis, before and after treatment, are at risk for getting an infection within the aorta or the heart valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
People with Ebstein's anomaly, before and after treatment, are at risk for getting an infection within the heart valve (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
Septal defects
Some congenital cardiovascular defects let blood flow between the heart's right and left chambers. This happens when a baby is born with an opening between the wall (septum) that separates the right and left sides of the heart. This defect is sometimes called "a hole in the heart."
The two most common types of this defect are atrial septal defect and ventricular septal defect. Two variations are Eisenmenger's complex and atrioventricular canal defect.
- An opening exists between the heart's two upper chambers. This lets
some blood from the left atrium
(blood that's already been to the lungs) return via the hole to the right
atrium instead of flowing through the left ventricle
, out the aorta
and to the body. Many children with ASD have few, if any, symptoms. Closing
the atrial defect by open-heart surgery in childhood can prevent serious
problems later in life.
If
the opening is small, it doesn't strain the heart. In that case, the only
abnormal finding is a loud murmur. But if the opening is large, open-heart
surgery is recommended to close the hole and prevent serious problems. Some
babies with a large ventricular septal defect don't grow normally and may
become undernourished. Babies with VSD may develop severe symptoms or high
blood pressure in their lungs. Repairing a ventricular septal defect with
surgery usually restores the blood circulation to normal. The long-term
outlook is good, but long-term follow-up is required.
People with a ventricular septal defect are at risk for getting an infection of the heart's walls or valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures. After a VSD has been successfully fixed with surgery, antibiotics should no longer be needed.
People with Eisenmenger's complex, before and after treatment, are at risk for getting an infection within the aorta or the heart valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
- A large hole in the center of the heart exists where the wall between
the upper chambers joins the wall between the lower chambers. Also, the
tricuspid
and mitral
valves that normally separate the heart's upper and lower chambers aren't
formed as individual valves. Instead, a single large valve forms that
crosses the defect.
The large opening in the center of the heart lets oxygen-rich (red) blood from the heart's left side - blood that's just gone through the lungs - pass into the heart's right side. There, the oxygen-rich blood, along with venous (bluish) blood from the body, is sent back to the lungs. The heart must pump an extra amount of blood and may enlarge. Most babies with an atrioventricular canal don't grow normally and may become undernourished. Because of the large amount of blood flowing to the lungs, high blood pressure may occur there and damage the blood vessels.
In some babies the common valve between the upper and lower chambers doesn't close properly. This lets blood leak backward from the heart's lower chambers to the upper ones. This leak, called regurgitation or insufficiency, can occur on the right side, left side, or both sides of the heart. With a valve leak, the heart pumps an extra amount of blood, becomes overworked and enlarges.
In babies with severe symptoms or high blood pressure in the lungs, surgery must usually be done in infancy. The surgeon closes the large hole with one or two patches and divides the single valve between the heart's upper and lower chambers to make two separate valves. Surgical repair of an atrioventricular canal usually restores the blood circulation to normal. However, the reconstructed valve may not work normally.
Rarely, the defect may be too complex to repair in infancy. In this case, the surgeon may do a procedure called pulmonary artery banding to reduce the blood flow and high pressure in the lungs. When a child is older, the band is removed and corrective surgery is done. More medical or surgical treatment is sometimes needed.
People with atrioventricular canal defect, before and after treatment, are at risk for getting an infection within the heart's walls or valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
Cyanotic defects
Another type of heart defect is congenital cyanotic heart defects. In these defects, blood pumped to the body contains less oxygen than normal. This causes a condition called cyanosis , a blue discoloration of the skin. The term "blue babies" is often applied to infants with cyanosis.
Examples of cyanotic defects are tetralogy of Fallot, transposition of the great arteries, tricuspid atresia, pulmonary atresia, truncus arteriosus and total anomalous pulmonary venous connection.
has four components. The two major ones are: 1) a large hole, or
ventricular septal
defect, that lets blood pass from the right to the left ventricle
without going through the lungs, and 2) a narrowing (stenosis) (sten-O'sis)
at or just beneath the pulmonary
valve. This narrowing partially blocks the blood flow from the heart's right
side to the lungs. The other two components are: 3) the right ventricle is
more muscular than normal, and 4) the aorta
lies directly over the ventricular septal defect.
This results in cyanosis (blueness), which may appear soon after birth, in infancy or later in childhood. These "blue babies" may have sudden episodes of severe cyanosis with rapid breathing. They may even become unconscious. During exercise, older children may become short of breath and faint. These symptoms occur because not enough blood flows to the lungs to supply the child's body with oxygen.
Some infants with severe tetralogy of Fallot may need an operation to give temporary relief by increasing blood flow to the lungs with a shunt. This is done by making a connection between the aorta and the pulmonary artery. Then some blood from the aorta flows into the lungs to get more oxygen. This reduces the cyanosis and allows the child to grow and develop until the problem can be fixed when the child is older.
Most children with tetralogy of Fallot have open-heart surgery before school age. The operation involves closing the ventricular septal defect and removing the obstructing muscle. After surgery the long-term outlook varies, depending largely on how severe the defects were before surgery. Lifelong medical follow-up is needed.
People with tetralogy of Fallot, before and after treatment, are at risk for getting an infection within the aorta or the heart valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
The
positions of the pulmonary artery
and the aorta
are reversed. The aorta is connected to the right ventricle
, so most of the blood returning to the heart from the body is pumped back
out without first going to the lungs. The pulmonary artery is connected to
the left ventricle, so most of the blood returning from the lungs goes back
to the lungs again.
Infants born with transposition survive only if they have one or more connections that let oxygen-rich blood reach the body. One such connection may be a hole between the two atria , called atrial septal defect, or between the two ventricles , called ventricular septal defect. Another may be a vessel connecting the pulmonary artery with the aorta, called patent ductus arteriosus . Most babies with transposition of the great arteries are extremely blue (cyanotic) soon after birth because these connections are inadequate.
To improve the body's oxygen supply, a special procedure called balloon atrial septostomy is used. Two general types of surgery may be used to help fix the transposition. One is a venous switch or intra-atrial baffle procedure that creates a tunnel inside the atria. Another is an arterial switch. After surgery, the long-term outlook varies quite a bit. It depends largely on how severe the defects were before surgery. Lifelong follow-up is needed.
People with transposition of the great arteries, before and after treatment, are at risk for getting an infection on the heart's walls or valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
In this
condition, there's no tricuspid valve. That means no blood can flow from the
right atrium
to the right ventricle
. As a result, the right ventricle is small and not fully developed. The
child's survival depends on there being an opening in the wall between the
atria called an atrial septal
defect and usually an opening in the wall between the two ventricles called
a ventricular
septal defect. Because the circulation is abnormal, the blood can't get
enough oxygen, and the child looks blue (cyanotic)
.
Often in these cases a surgical shunting procedure is needed to increase blood flow to the lungs. This reduces the cyanosis. Some children with tricuspid atresia have too much blood flowing to the lungs. They may need a procedure (pulmonary artery banding) to reduce blood flow to the lungs. Other children with tricuspid atresia may have a more functional repair (Fontan procedure). Children with tricuspid atresia require lifelong follow-up by a cardiologist.
People with tricuspid atresia, before and after treatment, are at risk for getting an infection of the valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
An opening in the atrial septum lets blood exit the right atrium , so venous (bluish) blood mixes with the oxygen-rich (red) blood in the left atrium. The left ventricle pumps this mixture of oxygen-poor blood into the aorta and out to the body. The baby appears blue (cyanotic) because there's less oxygen in the blood circulating through the arteries. The only source of lung blood flow is the patent ductus arteriosus (PDA), an open passageway between the pulmonary artery and the aorta. If the PDA narrows or closes, the lung blood flow is reduced to critically low levels. This can cause very severe cyanosis.
Early treatment often includes using a drug to keep the PDA from closing. A surgeon can create a shunt between the aorta and the pulmonary artery to help increase blood flow to the lungs. A more complete repair depends on the size of the pulmonary artery and right ventricle. If the pulmonary artery and right ventricle are very small, it may not be possible to correct the defect with surgery. In cases where the pulmonary artery and right ventricle are more normal size, open-heart surgery may produce a good improvement in how the heart works.
If the right ventricle stays too small to be a good pumping chamber, then the surgeon can connect the right atrium directly to the pulmonary artery. The atrial defect also can be closed to relieve the cyanosis. This is called a Fontan procedure. Children with tricuspid atresia require lifelong follow-up by a cardiologist.
People with pulmonary atresia, before and after treatment, are at risk for getting an infection on the heart's walls or valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
- This is a complex malformation where only one artery arises from the
heart and forms the aorta (a-OR'tah) and pulmonary artery
. Surgery for this condition usually is required early in life. It includes
closing a large ventricular septal
defect within the heart, detaching the pulmonary arteries from the large
common artery, and connecting the pulmonary arteries to the right ventricle
with a tube graft. Children with truncus arteriosus need lifelong follow-up
to see how well the heart is working.
People with truncus arteriosus, before and after treatment, are at risk for getting an infection on the heart's walls or valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.
In the right atrium, oxygen-rich (red) blood from the pulmonary veins mixes with venous (bluish) blood from the body. Part of this mixture passes through the atrial septum (atrial septal defect) into the left atrium. From there it goes into the left ventricle , to the aorta and out to the body. The rest of the poorly oxygenated mixture flows through the right ventricle, into the pulmonary artery and on to the lungs. The blood passing through the aorta to the body doesn't have enough oxygen, which causes the child to look blue (cyanotic) .
This defect must be surgically repaired in early infancy. The pulmonary veins are reconnected to the left atrium and the atrial septal defect is closed. When surgical repair is done in early infancy, the long-term outlook is very good. Still, lifelong follow-up is needed to make certain that any remaining problems, such as an obstruction in the pulmonary veins or irregularities in heart rhythm, are treated properly. It's important to make certain that a blockage doesn't develop in the pulmonary veins or where they're attached to the left atrium. Heart rhythm irregularities (arrhythmias) also may occur at any time after surgery.
Hypoplastic left heart syndrome
In hypoplastic left heart syndrome, the left side of the heart - including the aorta , aortic valve, left ventricle and mitral valve - is underdeveloped. Blood returning from the lungs must flow through an opening in the wall between the atria , called an atrial septal defect. The right ventricle pumps the blood into the pulmonary artery , and blood reaches the aorta through a patent ductus arteriosus . (See above.)
The
baby often seems normal at birth, but will come to medical attention within a
few days of birth as the ductus closes. Babies with this syndrome become ashen,
have rapid and difficult breathing and have difficulty feeding. This heart
defect is usually fatal within the first days or months of life without
treatment.
This defect isn't correctable, but some babies can be treated with a series of operations or with a heart transplant. Until an operation is performed, the ductus is kept open by intravenous (IV) medication. Because these operations are complex and different for each patient, you need to discuss all the medical and surgical options with your child's doctor. Your doctor will help you decide which is best for your baby.
If you and your child's doctor choose surgery, it will be done in several stages. The first stage, called the Norwood procedure, allows the right ventricle to pump blood to both the lungs and the body. It must be performed soon after birth. The final stage(s) has many names including bi-directional Glenn, Fontan operation and lateral tunnel. These operations create a connection between the veins returning blue blood to the heart and the pulmonary artery. The overall goal of the operation is to allow the right ventricle to pump only oxygenated blood to the body and to prevent or reduce mixing of the red and blue blood. Some infants require several intermediate operations to achieve the final goal.
Some doctors will recommend a heart transplant to treat this problem. Although it does provide the infant with a heart that has normal structure, the infant will require lifelong medications to prevent rejection. Many other problems related to transplants can develop. You should discuss these with your doctor.
Children with hypoplastic left heart syndrome require lifelong follow-up by a cardiologist for repeated checks of how their heart is working. Virtually all the children will require heart medicines.
People with hypoplastic left heart syndrome, before and after treatment, are at risk for getting an infection on the heart's inner lining or valves (endocarditis) . To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures. Good dental hygiene also lowers the risk of endocarditis. For more information about dental hygiene and preventing endocarditis, ask your pediatric cardiologist.
See also in this Web site:
AHA Scientific Statements: