How the heart works
To understand congenital heart defects, it's helpful to know how the normal heart works.
Your child's heart is a muscle about the size of his or her fist. It works like a pump and beats 100,000 times a day.
The heart has two sides, separated by an inner wall called the septum. The right side of the heart pumps blood to the lungs to pick up oxygen. Then, oxygen-rich blood returns from the lungs to the left side of the heart, and the left side pumps it to the body.
The heart has four chambers and four valves and is connected to various blood vessels. Veins are the blood vessels that carry blood from the body to the heart. Arteries are the blood vessels that carry blood away from the heart to the body.
The illustration shows a cross-section of a healthy heart and its inside structures. The blue arrow shows the direction in which oxygen-poor blood flows from the body to the lungs. The red arrow shows the direction in which oxygen-rich blood flows from the lungs to the rest of the body.
The heart has four chambers or "rooms."
- The atria (AY-tree-uh) are the two upper chambers that collect blood as it comes into the heart.
- The ventricles (VEN-trih-kuls) are the two lower chambers that pump blood out of the heart to the lungs or other parts of the body.
Four valves control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart.
- The tricuspid (tri-CUSS-pid) valve is in the right side of the heart, between the right atrium and the right ventricle.
- The pulmonary (PULL-mun-ary) valve is in the right side of the heart, between the right ventricle and the entrance to the pulmonary artery, which carries blood to the lungs.
- The mitral (MI-trul) valve is in the left side of the heart, between the left atrium and the left ventricle.
- The aortic (ay-OR-tik) valve is in the left side of the heart, between the left ventricle and the entrance to the aorta, the artery that carries blood to the body.
Valves are like doors that open and close. They open to allow blood to flow through to the next chamber or to one of the arteries, and then they shut to keep blood from flowing backward.
When the heart's valves open and close, they make a "lub-DUB" sound that a doctor can hear using a stethoscope.
- The first sound - the "lub" - is made by the mitral and tricuspid valves closing at the beginning of systole (SIS-toe-lee). Systole is when the ventricles contract, or squeeze, and pump blood out of the heart.
- The second sound - the "DUB" - is made by the aortic and pulmonary valves closing at beginning of diastole (di-AS-toe-lee). Diastole is when the ventricles relax and fill with blood pumped into them by the atria.
The arteries are major blood vessels connected to your heart.
- The pulmonary artery carries blood pumped from the right side of the heart to the lungs to pick up a fresh supply of oxygen.
- The aorta is the main artery that carries oxygen-rich blood pumped from the left side of the heart out to the body.
- The coronary arteries are the other important arteries attached to the heart. They carry oxygen-rich blood from the aorta to the heart muscle, which must have its own blood supply to function.
The veins are also major blood vessels connected to your heart.
- The pulmonary veins carry oxygen-rich blood from the lungs to the left side of the heart so it can be pumped out to the body.
- The vena cava is a large vein that carries oxygen-poor blood from the body back to the heart.
What are the types of congenital heart defects?
Congenital heart defects change the normal flow of blood through the heart because some part of the heart didn't develop properly before birth.
There are many types of congenital heart defects. They include simple ones such as a hole in the interior walls of the heart that allows blood from the left and right sides of the heart to mix, or a narrowed valve that blocks the flow of blood to the lungs or other parts of the body.
Other defects are more complex. These include combinations of simple defects, problems with where the blood vessels leading to and from the heart are located, and more serious abnormalities in how the heart develops.
Examples of Simple Congenital Heart Defects
Holes in the Heart (Septal Defects)
The septum is the wall that separates the chambers on the left side of the heart from those on the right. It prevents mixing of blood between the two sides of the heart. Sometimes, a baby is born with a hole in the septum. When that occurs, blood can mix between the two sides of the heart.
Atrial septal defect (ASD). An ASD is a hole in the part of the septum that separates the atria - the upper chambers of the heart. This heart defect allows oxygen-rich blood from the left atrium to flow into the right atrium instead of flowing to the left ventricle as it should. Many children who have ASDs have few, if any, symptoms.
Normal Heart and Heart With Atrial Septal Defect
Figure A shows the normal structure and blood flow in the interior of the heart. Figure B shows a heart with an atrial septal defect, which allows oxygen-rich blood from the left atrium to mix with oxygen-poor blood from the right atrium.
An ASD can be small or large. Small ASDs allow only a little blood to leak from one atrium to the other. Very small ASDs don't affect the way the heart works and therefore don't need any special treatment. Many small ASDs close on their own as the heart grows during childhood. Medium to large ASDs allow more blood to leak from one atrium to the other, and they're less likely to close on their own.
Half of all ASDs close on their own or are so small that no treatment is needed. Medium to large ASDs that need treatment can usually be repaired using a catheter procedure. (See "How Are Congenital Heart Defects Treated?")
Ventricular septal defect (VSD). A VSD is a hole in the part of the septum that separates the ventricles - the lower chambers of the heart. The hole allows oxygen rich blood to flow from the left ventricle into the right ventricle instead of flowing into the aorta and out to the body as it should.
Normal Heart and Heart With Ventricular Septal Defect
Figure A shows the normal structure and blood flow in the interior of the heart. Figure B shows two common locations for a ventricular septal defect. The defect allows oxygen-rich blood from the left ventricle to mix with oxygen-poor blood in the right ventricle.
A VSD can be small or large. A small VSD doesn't cause problems and may often close on its own. Large VSDs cause the left side of the heart to work too hard and increase blood pressure in the right side of the heart and the lungs because of the extra blood flow. The increased work of the heart can cause heart failure and poor growth. If the hole isn't closed, the high blood pressure in the lungs can cause the delicate arteries in the lungs to scar, a condition called pulmonary arterial hypertension. Open-heart surgery is used to repair VSDs.
Simple congenital heart defects also can involve the heart's valves, which control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart (the aorta and the pulmonary artery). Valves can have the following types of defects:
- Stenosis. This is when the valve doesn't open completely, and the heart has to work harder to pump the blood through the valve.
- Atresia. This is when the valve doesn't form correctly, so there is no opening for blood to pass through.
- Regurgitation (re-GUR-ji-TA-shun). This is when the valve doesn't close completely, so blood leaks back through the valve.
The most common valve defect is called pulmonary valve stenosis, which is a narrowing of the pulmonary valve. This valve allows blood to flow from the right ventricle into the pulmonary arteries and out to the lungs to pick up oxygen.
Pulmonary valve stenosis can range from mild to severe. Most children with this defect have no signs or symptoms other than a heart murmur. Treatment isn't needed if the stenosis is mild.
In a baby with severe pulmonary valve stenosis, the right ventricle can get very overworked trying to pump blood to the pulmonary arteries. Oxygen-poor blood can back up from the right side of the heart into the left side, causing cyanosis. Cyanosis is a bluish tint to the skin, lips, and fingernails. It occurs because the oxygen level in the blood leaving the heart is below normal.
Older children with severe pulmonary valve stenosis may have symptoms such as fatigue (tiredness) when exercising. Severe pulmonary valve stenosis is treated with a catheter procedure.
Example of a Complex Congenital Heart Defect
Complex congenital heart defects need to be repaired with surgery. Because of advances in diagnosis and treatment, doctors can now successfully repair even very complex congenital heart defects.
The most common complex heart defect is tetralogy of Fallot (teh-TRALL-o-gee of fall-O), a combination of four defects:
- Pulmonary valve stenosis.
- A large VSD.
- An overriding aorta. The aorta sits above both the left and right ventricles over the VSD, rather than just over the left ventricle. As a result, oxygen poor blood from the right ventricle can flow directly into the aorta instead of into the pulmonary artery to the lungs.
- Right ventricular hypertrophy. The muscle of the right ventricle is thicker than usual because of having to work harder than normal.
These defects prevent enough blood from flowing to the lungs to get oxygen, while oxygen-poor blood flows directly out to the body.
Normal Heart and Heart With Tetralogy of Fallot
Figure A shows the normal structure and blood flow in the interior of the heart. Figure B shows a heart with the four defects of tetralogy of Fallot.
Babies and children with tetralogy of Fallot have episodes of cyanosis, which can sometimes be severe. In the past, when this condition wasn't treated in infancy, older children would get very tired during exercise and could have fainting spells. Tetralogy of Fallot is now repaired in infancy to prevent these types of symptoms.
Tetralogy of Fallot must be repaired with open heart surgery, either soon after birth or later in infancy, depending on how severely the pulmonary artery is narrowed. Children who have had this heart defect repaired need lifelong medical care from a specialist to make sure they stay as healthy as possible.
What are other names for congenital heart defects?
- Congenital heart disease
- Cyanotic heart disease
- Heart defects
- Congenital cardiovascular malformations
What causes congenital heart defects?
If you have a child with a congenital heart defect, you may think you did something wrong during your pregnancy to cause the problem. However, most of the time doctors don't know why congenital heart defects develop.
Heredity may play a role in some heart defects. For example, a parent who has a congenital heart defect may be more likely than other people to have a child with the condition. In rare cases, more than one child in a family is born with a heart defect. Children with genetic defects often have congenital heart defects. An example of this is Down syndrome - half of all babies with Down syndrome have congenital heart defects.
Scientists continue to search for the causes of congenital heart defects.
What are the signs and symptoms and signs of congenital heart defects?
Many congenital heart defects have few or no symptoms. A doctor may not even detect signs of a heart defect during a physical exam.
Some heart defects do have symptoms. These depend on the number and type of defects and how severe the defects are. Severe defects can cause symptoms, usually in newborn babies. These symptoms can include:
- Rapid breathing
- Cyanosis (a bluish tint to the skin, lips, and fingernails)
- Fatigue (tiredness)
- Poor blood circulation
Congenital heart defects don't cause chest pain or other painful symptoms.
Abnormal blood flow through the heart caused by a heart defect will make a certain sound. Your doctor can hear this sound, called a heart murmur, with a stethoscope. However, not all murmurs are a sign of a congenital heart defect. Many healthy children have heart murmurs.
Normal growth and development depend on a normal workload for the heart and normal flow of oxygen-rich blood to all parts of the body. Babies with congenital heart defects may have cyanosis or tire easily when feeding. Sometimes they have both problems. As a result, they may not gain weight or grow as they should.
Older children may get tired easily or short of breath during exercise or activity. Many types of congenital heart defects cause the heart to work harder than it should. In severe defects, this can lead to heart failure, a condition in which the heart can't pump blood strongly throughout the body. Symptoms of heart failure include:
- Fatigue with exercise
- Shortness of breath
- A buildup of blood and fluid in the lungs
- A buildup of fluid in the feet, ankles, and legs
How are congenital heart defects diagnosed?
Serious congenital heart defects are generally identified during pregnancy or soon after birth. Less severe defects aren't diagnosed until children are older. Minor defects often have no symptoms and are diagnosed based on results from a physical exam and special tests done for another reason.
Doctors who specialize in the care of babies and children who have heart problems are called pediatric cardiologists. Other specialists who treat heart defects in children include cardiac surgeons (doctors who repair heart defects using surgery).
- During a physical exam, the doctor:
- Listens to your child's heart and lungs with a stethoscope
Looks for other signs of a heart defect, such as cyanosis (a bluish tint to the skin, lips, or fingernails), shortness of breath, rapid breathing, delayed growth, or signs of heart failure
Tests Commonly Used To Diagnosis Congenital Heart Defects
This test, which is harmless and painless, uses sound waves to create a moving picture of your child's heart. During an echocardiogram, reflected sound waves show the structure of the heart. 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 an important test for both diagnosing a heart problem and following the problem over time. In children with congenital heart defects, an echocardiogram will outline the problems with the heart's structure and show how the heart is reacting to these problems. The echocardiogram will help your child's cardiologist decide 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 fourth or 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.
An EKG detects and records the electrical activity of the heart. An EKG shows how fast the heart is beating and whether the heart's rhythm is steady or irregular. It can also detect if one of the heart's chambers is enlarged, which can help diagnose a heart problem.
Chest X Ray
A chest x ray takes a picture of the heart and lungs. It can show whether the heart is enlarged or whether the lungs have extra blood or fluid, which can be a sign of heart failure.
Pulse oximetry shows how much oxygen is in the blood. A sensor is placed on the child's fingertip or toe (like an adhesive bandage). The sensor is attached to a small computer unit, which displays a number that indicates how much oxygen is in the blood.
During cardiac catheterization (KATH-e-ter-i-ZA-shun), a thin, flexible tube called a catheter is passed through a vein in the arm, groin (upper thigh), or neck to reach the heart. A dye that can be seen on an x ray is injected through the catheter into a blood vessel or a chamber of the heart. This allows the doctor to see the flow of blood through the heart and blood vessels.
Cardiac catheterization also can be used to measure the pressure inside the heart and blood vessels and to determine whether blood is mixing between the two sides of the heart. It's also used to repair some heart defects.
How are congenital heart defects treated?
Although many children with congenital heart defects don't need treatment, some do. Doctors treat congenital heart defects with:
- Procedures using catheters to repair the defect
- Surgery to repair the defect
The treatment your child receives depends on the type and severity of his or her heart defect. Other factors include your child's age, size, and general health. Treatment can be simple or very complex. Some children with complex congenital heart defects may need several catheter or surgical procedures over a period of years, or may need to take medicines for years.
Procedures Using Catheters
Catheter procedures are much easier than surgery on patients because they involve only a needle puncture in the skin where the catheter is inserted into a vein or an artery. Doctors don't have to surgically open the chest or operate directly on the heart to repair the defect. This means that recovery can be much easier and quicker.
The use of catheter procedures has grown a lot in the past 20 years. They have become the preferred way to repair many simple heart defects, such as:
- Atrial septal defect. The doctor inserts the catheter through a vein and threads it up into the heart to the septum. The catheter has a tiny umbrella?like device folded up inside it. When the catheter reaches the septum, the device is pushed out of the catheter and positioned so that it plugs the hole between the atria. The device is secured in place and the catheter is then withdrawn from the body.
- Pulmonary valve stenosis. The doctor inserts the catheter through a vein and threads it into the heart to the pulmonary valve. A tiny balloon at the end of the catheter is quickly inflated to push apart the leaflets, or "doors," of the valve. The balloon is then deflated and the catheter is withdrawn. Procedures like this can be used to repair any narrowed valve in the heart.
Doctors often use an echocardiogram or a transesophageal (trans-e-SOF-ah-ge-al) echocardiogram (TEE) as well as an angiogram to guide them in threading the catheter and doing the repair. A TEE is a special type of echocardiogram that takes pictures of the back of the heart through the esophagus (the tube leading from the mouth to the stomach). TEE also is often used to define complex heart defects.
Catheter procedures also are sometimes used during surgery to help repair complex defects.
A child may need open-heart surgery if his or her heart defect can't be fixed using a catheter procedure. Sometimes, one surgery can repair the defect completely. If that's not possible, a child may need more than one surgery over a period of months or years to fix the problem.
Open-heart surgery may be done to:
- Close holes in the heart with stitches or with a patch
- Repair or replace heart valves
- Widen arteries or openings to heart valves
- Repair complex defects, such as problems with where the blood vessels near the heart are located and how they develop
Rarely, babies are born with multiple defects that are too complex to repair. These babies may need a heart transplant. In this procedure, the child's heart is replaced with a healthy heart from a deceased child that has been donated by that child's family.
Living with a congenital heart defect
The outlook for a child with a congenital heart defect is much better today than in past years. Advances in testing and treatment mean that most children with heart defects grow into adulthood and are able to live active, productive lives. Many need no special care or only occasional checkups with a cardiologist as they grow up and go through adult life.
The small number of children who have complex heart defects need long-term, special care by trained specialists to stay as healthy as possible and maintain a good quality of life.
Children and Teens With Congenital Heart Defects
Routine Medical Care
Ongoing medical care is important for your child's health. This includes:
- Checkups with your child's heart specialist as directed
- Checkups with your child's pediatrician or family doctor for routine exams
- Taking medicines as prescribed
Most children with severe heart defects are at increased risk for bacterial endocarditis, a serious infection of the heart valves or lining of the heart. Your child's doctor or dentist may give your child antibiotics before medical or dental procedures (such as surgery or dental cleanings) that could allow bacteria into the bloodstream. Talk to your child's doctor about whether your child needs to take antibiotics before such procedures.
As children with heart defects grow up and become teens, it's important that they understand what kind of defect they have, how it was treated, and what kind of care may still be needed. This understanding will help the teen take responsibility for his or her health. It also will help ensure a smooth transition from care by a pediatric cardiologist to care by an adult cardiologist. Young adults with complex congenital heart defects require ongoing care by doctors who specialize in adult congenital heart defects.
You may want to work with your health care providers to put together a packet with medical records and information that covers all aspects of your child's heart defect, including:
- Procedures or surgeries
- Prescribed medicines
- Recommendations about medical followup and how to prevent complications
- Health insurance
Keeping your health insurance current is important. For example, if your child is covered under health insurance through your employer and you plan to change jobs, find out if health insurance through your new employer will cover care for your child's congenital heart defect. Some health insurance plans may not cover medical conditions that you or your family member had before joining the new plan.
It's also very important for your child to have health insurance as adulthood approaches. Review your current health insurance plan. Find out how coverage can be extended to your child beyond the age of 18. Some policies may allow you to keep your child on your plan if he or she remains in school or is disabled.
Feeding and Nutrition
Some babies and children with congenital heart defects don't grow and develop as fast as other children who are the same age. If your child's heart has to pump harder than normal because of the defect, he or she may tire quickly when feeding or eating and not be able to eat enough.
As a result, your child may be smaller and thinner than other children. Your child also may start activities such as rolling over, sitting, and walking later than other children. After treatments and surgery, growth and development often improve.
To help your baby get enough calories, discuss with his or her doctor the best feeding schedule and any supplements your baby may need. Make sure your child has nutritious meals and snacks as he or she grows to help with growth and development.
Exercise and Physical Activity
Exercise helps children strengthen their muscles and stay healthy. Discuss with your child's doctor how much and what kinds of physical activities are best for your child. Some children and teens with congenital heart defects may need to limit the amount or type of exercise they do.
Remember to ask the doctor for a note for school and other organizations describing any limits on your child's exercise or physical activities.
It's common for children and teens with serious conditions or illnesses to have a hard time emotionally or to feel isolated if they have to be in the hospital a lot. Some feel sad or frustrated with their body image and their inability to be a "normal" kid. Sometimes brothers or sisters are jealous of a child who needs a lot of attention for medical problems.
If you have concerns about your child's emotional health, talk to his or her doctor.
Adults With Congenital Heart Defects
Adults with congenital heart defects who needed regular medical checkups in their youth may need to keep seeing a specialist who can care for their health. They will need to pay attention to the following issues.
Sometimes people mistakenly believe that the surgery they had in childhood for their congenital heart defect was a "cure." They don't realize that regular medical followup may be needed in adulthood to maintain good health.
Some adults may not know what kind of heart defect they had (or still have) or how it was repaired. They should learn about their medical history and know as much as possible about any medicines they're taking.
Preventing Bacterial Endocarditis
Some people may need antibiotics before medical or dental procedures that could allow bacteria to enter the bloodstream. Talk to your doctor about whether you need to take antibiotics before such procedures. Regular brushing, flossing, and visits to the dentist also can help prevent bacterial endocarditis.
Contraception and Pregnancy
Women who have heart defects should talk with their doctors about the safest type of birth control. Many women can safely use most methods, but some women should avoid certain types of birth control, such as birth control pills or intrauterine devices (IUDs).
Many women with simple heart defects can have a normal pregnancy and delivery. Women with congenital heart defects who want to become pregnant (or who are pregnant) should talk with their doctor about the health risks. They also may want to consult with specialists who help pregnant women with congenital heart defects.
Health Insurance and Employment
When thinking about changing jobs, adults with congenital heart defects should carefully consider the impact on their health insurance coverage. Some health plans have waiting periods or clauses to exclude some kinds of coverage. Before making any job changes, find out whether the change will affect your health insurance coverage.
Several laws protect the employment rights of people who have congenital heart defects. The Americans with Disabilities Act and the Work Incentives Improvement Act try to ensure fairness in hiring for all people, including those with health conditions such as heart defects.
Congenital Heart Disease At A Glance
- Congenital heart defects are problems with the heart's structure that are present at birth. Congenital heart defects change the normal flow of blood through the heart.
- Congenital heart defects are the most common type of birth defect, affecting 8 out of every 1,000 newborns. Each year, more than 35,000 babies in the United States are born with congenital heart defects.
- There are many types of congenital heart defects ranging from simple to very complex.
- Doctors don't know what causes most congenital heart defects. Heredity may play a role.
- Although many heart defects have few or no symptoms, some do. Severe defects can cause symptoms such as:
- Rapid breathing.
- A bluish tint to skin, lips, and fingernails. This is called cyanosis.
- Fatigue (tiredness).
- Poor blood circulation.
- Serious heart defects are usually diagnosed while a baby is still in the womb or soon after birth. Some defects aren't diagnosed until later in childhood, or even in adulthood.
- An echocardiogram is an important test for both diagnosing a heart problem and following the problem over time. This test helps diagnose problems with how the heart is formed and how well it's working. Other tests include EKG (electrocardiogram), chest x ray, pulse oximetry, and cardiac catheterization.
- Doctors treat congenital heart defects with catheter procedures and surgery.
- Treatment depends on the type and severity of the defect.
- With new advances in testing and treatment, most children with congenital heart defects grow into adulthood and can live healthy, productive lives. Some need special care all though their lives to maintain a good quality of life.
SOURCE: US Department of Health and Human Services. National Heart Lung and Blood Institute