Category:Cardiovascular
From Holoprosencephaly
What Is a Congenital Heart Defect?
A congenital heart defect is a structural problem (or defect) in the heart that is present at birth. A baby's heart begins to develop shortly after conception. During development, structural defects can occur. These defects can involve the walls of the heart, the valves of the heart, and the arteries and veins near the heart. Congenital heart defects can disrupt the normal flow of blood through the heart. The blood flow can:
- Slow down
- Go in the wrong direction or to the wrong place
- Be blocked completely
Congenital heart defect is the most common type of major birth defect. Each year, more than 30,000 babies in the United States are born with congenital heart defects.
Types of Congenital Heart Defects
There are many types of congenital heart defects. They include:
- Abnormal passages in the heart or between blood vessels
- Problems with the heart valves
- Problems with the placement or development of blood vessels near the heart
- Problems with development of the heart itself
To better understand the effects of these problems, see "How the Heart Works".
Some of these problems are described below.
Abnormal passages in the heart or between blood vessels
- Atrial septal defect (ASD) is a hole in the wall that separates the upper chambers (atria (AY-tree-uh)) of the heart. This causes blood to leak from one atrium to the other.
- Ventricular septal defect (VSD) is a hole in the wall that separates the lower chambers (ventricles (VEN-trih-kuls)) of the heart. This causes blood to leak from one ventricle to the other.
- Atrioventricular septal defect (AVSD) includes an ASD, VSD, and abnormal development of the atrioventricular valves tricuspid and mitral. This causes blood to flow abnormally inside the heart. An AVSD is also known as an atrioventricular canal defect.
- Patent ductus arteriosus (PDA) is a persistent connection between the aorta and the pulmonary artery. This connection is called the ductus arteriosus and is normally present before birth. In most babies, the vessel closes within a few hours or days after birth. In some children, the vessel fails to close, resulting in PDA.
Problems with the heart valves
Congenital heart defects can involve any of the valves and include the following types of problems:
- Stenosis. The valve opening is narrow and does not open completely.
- Atresia. The valve does not form, so there is no opening for blood to pass from one chamber to another.
- Regurgitation. The valve does not close completely, so blood can leak back through the valve.
Examples of particular heart valve problems include:
- Aortic valve stenosis is a narrowing of the aortic valve in the heart that causes it to open incompletely. This can reduce blood flow to the body.
- Pulmonary valve atresia is a defect in which a solid sheet of tissue forms in place of the pulmonary valve. This prevents blood in the right side of the heart from traveling normally to the lungs to pick up oxygen.
- Pulmonary valve stenosis is a narrowing of the pulmonary valve. The narrowing slows the flow of blood from the right side of the heart to the lungs. The heart must pump harder to push blood through the smaller opening.
- Tricuspid valve atresia is a defect in which a solid sheet of tissue forms in place of the tricuspid valve. Without the tricuspid valve, blood entering the right atrium cannot travel normally to the right ventricle and then to the lungs to pick up oxygen.
- Ebstein's anomaly is a defect in which the tricuspid valve is both displaced and abnormally formed. The valve leaks and allows blood to flow back into the right atrium instead of to the lungs to pick up oxygen.
Problems with placement or development of blood vessels near the heart
- Transposition of the great vessels is a defect in which the location of the "great vessels" (the aorta and pulmonary artery) coming off the heart is switched. The aorta comes off the right ventricle instead of the left ventricle. The pulmonary artery comes off the left ventricle instead of the right ventricle. Therefore, blood without oxygen is continually pumped to the body, instead of blood with oxygen.
- Tetralogy of Fallot is a combination of four defects:
- Pulmonary valve stenosis is the narrowing of the pulmonary valve. The narrowing slows the flow of blood from the right ventricle to the lungs.
- VSD is a hole in the wall that separates the left and right ventricles.
- Overriding aorta is a defect in which the aorta is positioned between the left and right ventricles, over the VSD.
- Right ventricular hypertrophy is the thickening of the right ventricle. The thickening is caused by the heart having to work harder because of the other defects.
- Truncus arteriosus is a defect of the great vessels. The aorta and pulmonary artery do not form as separate arteries. Instead, a large artery, called the truncus, comes from the heart. As the truncus leaves the heart, it may branch into arteries that carry blood to the body and to the lungs.
- Coarctation of the aorta is a narrowing of the aorta. It slows or blocks the flow of blood from the heart to the body.
- Anomalous pulmonary venous return is a defect in which one or more of the four pulmonary veins, which normally return oxygen-rich blood from the lungs to the heart, return to the wrong chamber in the heart.
Problems with development of the heart
- Hypoplastic left heart syndrome is a combination of defects in which the left side of the heart does not develop properly. Defects usually include mitral atresia, aortic atresia, and a tiny left ventricle.
- Mitral atresia occurs when a solid sheet of tissue forms instead of the mitral valve, which separates the left atrium and the left ventricle.
- Aortic atresia occurs when a solid sheet of tissue forms instead of the aortic valve, which separates the left ventricle from the aorta.
- Single ventricle describes a group of heart defects in which only one ventricle is present instead of two. It can be a single right or a single left ventricle. The other ventricle is usually absent or very tiny. Hypoplastic left heart syndrome is an example of a single ventricle defect.
Today, the outlook for an infant born with a heart defect is much better than it was 30 years ago. Rapid advances in infant and childhood surgery, better tests, and new medicines help most children with congenital heart defects. Many children born with more complex or severe heart defects now reach adulthood. Today, there are more than 1 million adults living with congenital heart defects.
How Are Congenital Heart Defects Diagnosed?
Doctors usually diagnose congenital heart defects during pregnancy or within the first few months after birth. Some children with less severe defects are not diagnosed until they are older and more demands are put on their hearts. Others are not diagnosed until they are adults.
If your child's doctor suspects a congenital heart defect, he or she will refer your child to a specialist who treats heart problems in children. The specialist, a pediatric cardiologist, will take a family and medical history, do a physical exam, and order several tests.
Physical Exam
During the physical exam, the doctor:
- Listens to your child's heart with a stethoscope for a heart murmur
- Looks for signs of illness or physical problems, such as bluish color of skin and lips, shortness of breath, rapid breathing, and delayed growth
- Listens to your child's lungs
Tests
An echocardiogram which is harmless and painless, uses sound waves to create a moving picture of your child's heart. During an echocardiogram, reflected sound waves outline the heart's structure completely. The test allows the doctor to clearly see any problem with the way the heart is formed or the way it's working. An echocardiogram is the most important test available to your child's cardiologist to both diagnose a heart problem and follow the problem over time. In children with congenital heart defects, an echocardiogram will outline each problem with the heart's structure and show how the heart is reacting to these problems. The echocardiogram will help your child's cardiologist to know if and when treatment is needed.
During pregnancy, if your doctor suspects that your baby has a congenital heart defect, a special test called a fetal echocardiogram can be done. This test uses sound waves to create a picture of the baby's heart while the baby is still in the womb. The test is usually done during the fifth month of pregnancy. If your child is diagnosed with a congenital heart defect before birth, your doctor can plan treatment before the baby is born.
Other tests used to help diagnose congenital heart defects include:
- EKG (electrocardiogram) An EKG test measures the rate and regularity of your child's heartbeat.
- Chest x ray A chest x ray takes a picture of your child's heart and lungs. It can show if the heart is enlarged or if there is fluid in the lungs.
- Pulse oximetry This test uses a sensor to see how well your child's lungs are passing oxygen to the blood and whether there is any mixing of oxygen-rich and oxygen-poor blood. The sensor is placed on the child's fingertip or toe (like an adhesive bandage). A small computer unit shows the amount of oxygen in the blood through the skin. The test does not hurt.
- Cardiac Catheterization In this test, a thin flexible tube is passed through an artery or vein at the upper thigh (groin) or in the arm to reach the heart. With the assistance of x rays, the doctor can then see your child's blood vessels and heart. The catheter also measures the pressure inside the heart and blood vessels and can determine if blood is mixing between the two sides of the heart. Sometimes, a dye that can be seen by x ray is injected into the heart. This enables the doctor to see the flow of blood throughout the heart and blood vessels.
How Are Congenital Heart Defects Treated?
Doctors treat congenital heart defects with:
- Medicines
- Special procedures using catheters
- Surgery
- Heart transplants
The treatment your child receives depends on the type and severity of the defect. Other factors include your child's age, size, and general health. Treatment can be simple or very complex. Many children are treated with medicines and are monitored by their doctor. Other children may need surgery.
Medicines
Your child may take one or more of the following medicines to help the heart work better and lessen symptoms:
- Digoxin is thought to improve heart function and can keep the heartbeat regular.
- Diuretics treat the buildup of fluid in the heart and body.
- ACE inhibitors decrease the work the heart has to do and may help remodel the heart and blood vessels to work more efficiently.
- Beta blockers slow the heart rate and lower blood pressure to decrease the workload on the heart.
- Inotropes strengthen the heart's pumping ability.
- Prostaglandin E1 is used to keep the ductus arteriosus open in some defects until corrective surgery can be performed. This improves blood flow and oxygen levels until the defect is corrected. The ductus arteriosus normally closes within a few days after birth.
Special Procedures Using Catheters
Doctors can correct some congenital heart defects during cardiac catheterization. These are called catheter-based procedures or interventions. They can be used instead of open-heart surgery, which is a major operation. A catheter is inserted through a blood vessel in your child's groin. It is then threaded to the heart, where some holes in the interior walls of the heart can be fixed, a patent ductus arteriosus can be closed, and narrow valves and blood vessels can be opened up. Cardiac catheterization:
- Does not require your child's chest to be opened
- Lets your child recover quickly
- Has different risks than open-heart surgery
Surgery
Your child may need open-heart surgery if the defect can’t be repaired using a catheter-based procedure. Some surgeries repair the defect completely. Other surgeries improve the child's health but do not completely repair the defect. Open-heart surgery may be done to:
- Close holes with stitches or with a patch
- Repair valves
- Widen arteries or openings to valves
- Put the great vessels (aorta and pulmonary artery) in their correct positions
Sometimes, open-heart surgery can improve a child's health but not repair the problem. Examples include:
- Decreasing blood flow to the lungs by placing a band around the pulmonary artery
- Increasing blood flow to the lungs by connecting an artery from the aorta to the pulmonary artery
- Connecting the veins that bring oxygen-poor blood directly to the pulmonary artery in a three-stage surgery when the right ventricle is not developed (for example, hypoplastic left heart syndrome)
If you have any concerns, please don't hesitate to discuss your concerns with your child's doctor(s).
For information about dealing with potential health problems, treatments and medications, please visit our Miscellaneous Health Information category.
Click here to read what specialists have to say about caring for children with Holoprosencephaly: Doctor Q&A
Sources:
http://www.nhlbi.nih.gov/health/dci/Diseases/chd/chd_what.html
Resources:
http://www.congenitalheartdefects.com/
