Tetralogy of Fallot (TOF) with Pulmonary Atresia Symptoms & Causes

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It’s natural for you to be concerned right now about your child’s health—a diagnosis of tetralogy of Fallot with pulmonary atresia can be overwhelming. But you may rest assured that at Children’s Hospital Boston, your child is in expert hands. What follows is a brief description of the condition. Your child’s doctors will give you even more thorough information in person.

What is tetralogy of Fallot with pulmonary atresia?

Tetralogy of Fallot with pulmonary atresia means that five associated heart abnormalities occur:

  • ventricular septal defect (VSD—a hole between the right and left ventricles)
    • allows blue blood to go from the right ventricle into the aorta, reducing the amount of oxygen in the blood pumped to the body
  • overriding aorta (moves toward right side of heart; located just over the ventricular septal defect)
    • a minor abnormality that is of little surgical or other consequence
  • hypertrophy of the right ventricle (becomes abnormally enlarged because it’s attempting to compensate for the pulmonary obstruction)
    • the right ventricle is thicker than normal, since it has to pump blood at a higher pressure than normal
    • largely resolves after complete repair of the defect
  • complete pulmonary obstruction (no pulmonary valve or connection between the right ventricle and the pulmonary artery)
    • Blood finds its ways to the lungs by either a ductus arteriosus or multiple aortopulmonary collateral arteries (“MAPCAs”—arteries that develop to supply blood to the lungs when native pulmonary circulation is underdeveloped).
  • abnormal pulmonary arteries
    • Some patients have essentially normal pulmonary arteries, but ...
    • Usually there’s a combination of MAPCAs and very small “native” pulmonary arteries.
    • In order to best treat this problem, the MAPCAs and “native” pulmonary arteries are connected surgically, and then connected to the right ventricle.
    • The pattern of MAPCAs, native pulmonary arteries and areas of narrowing in these arteries largely determine the complexity of surgical therapy needed. The number, size, and arrangement of pulmonary arteries are extremely variable in this disease.
    • In many cases, some or all of the pulmonary arteries actually arise from the aorta, rather than the right ventricle; unlike in a normal situation, they are not connected with each other.

The pulmonary arteries are highly variable from child to child. In some children, they’re essentially normal, except for the fact that they are connected to the aorta (usually by a ductus arteriosus) rather than to the right ventricle.

In the majority of children, there are multiple arteries that arise from the aorta or its branches, and that go to the lungs (the multiple aortopulmonary collateral arteries, or “MAPCAs,” mentioned above). Many patients with MAPCAs also have something like a normal pulmonary artery, although it’s much smaller than normal and often goes to only some, rather than all, parts of the lung.

What are the signs and symptoms of ToF/PA?

Signs and symptoms of ToF/PA usually appear shortly after a baby is born, when the maternal source of oxygen (from the placenta) is removed. The most common sign is cyanosis (blue color to the skin, lips and nail beds) due to large amounts of oxygen-poor (blue) blood flowing to the body.

How do you diagnose ToF/PA?

For most patients, doctors use an EKG (electrocardiogram), chest x-ray, cardiac ultrasound (echocardiogram) and cardiac catheterization (sometimes multiple) with angiography to diagnose ToF/PA.

Your cardiologist will detect a heart murmur and measure blood oxygen levels (non-invasively). The doctor may also order additional diagnostic testing, which could include: cardiac MRI or chest CT scan.

How do you treat ToF/PA?

  • Surgery is standard of care for ToF/PA, and it’s usually performed within a baby’s first 6 months of life. The surgery brings all the pulmonary arteries together so that a connection can be created between the arteries and the right ventricle.
    • Your child may need more than one operation, sometimes over a period of months or years.
    • It is likely that more than one heart catheterization will be needed.
    • Your child will need close medical follow-up care.

For details, see the Treatment tab.

Will my child be OK after surgical repair for ToF/PA?

The outlook varies from child to child, but open heart surgery at Children’s has among the highest success rates in the United States among large pediatric cardiac centers.

Your child may need multiple operations or catheterizations as he grows older. And he will need to be followed by a Children’s pediatric cardiologist, who will determine care going forward.

What causes ToF/PA?

The heart starts to form during the first eight weeks of fetal growth. ToF/PA occurs when the heart fails to develop normally during this development period.

  • Most often this heart defect occurs sporadically (by chance), with no clear reason for its development.
  • In some cases, the defect may have a genetic link. One genetic link that has been associated with tetralogy of Fallot/PA is a deletion—or missing piece—of chromosome number 22 (22q11). This is present in a minority of patients but is thought to be more common in those with a severe form of tetralogy of Fallot with pulmonary atresia. The condition is known as the “22q11 deletion,” and blood tests are available to detect it.

How common is ToF/PA?

ToF/PA is a variant of ToF, a rare disease that affects about 2 in 10,000 children.

Will my baby need more care in the medium- and longer-term?

Yes. Your child may need multiple operations or catheterizations as he grows older.

  • Although the goal of the operation is to repair the defect, some patients will develop sufficient leakage from the pulmonary valve that it requires replacement. This usually occurs in adulthood, although it can occur sooner. Multiple heart catheterizations are often required for enlarging the pulmonary arteries using balloon catheters.
  • Your child will need lifelong monitoring and medication, since he may be at some risk for arrhythmias and other heart problems.
  • Non-cardiac surgeries and, for females, pregnancy may pose special risks and will require careful evaluation and discussion with a cardiologist.

Our Boston Adult Congenital Heart and Pulmonary Hypertension Service (BACH) can provide your child with any needed care as he reaches and progresses through adulthood.

Your child’s Children’s cardiologist will help you create a long-term care program as your baby grows into childhood, the teen years and adulthood. We’ll prevent and treat complications and will advise on daily-life issues, exercise and activity levels, nutrition and precautions related to pregnancy.

FAQ

Q: What is ToF/PA?
A:
A severe variant of tetralogy of Fallot, ToF/PA is a combination of five cardiac anatomic characteristics:

  • ventricular septal defect(VSD—a hole between right and left ventricles)
  • overriding aorta(moves toward right side of heart; located just over the ventricular septal defect)
  • hypertrophy of the right ventricle(becomes abnormally enlarged because it’s attempting to compensate for the pulmonary obstruction)
  • complete pulmonary obstruction(absent pulmonary valve; no connection between the right ventricle and the pulmonary artery)
  • abnormal pulmonary arteries

Q: If my child has ToF/PA, will he be OK?
A:
The outlook varies from child to child, but open heart surgery at Children’s has among the highest success rates in the United States among large pediatric cardiac centers.

Your child may need multiple operations or catheterizations as he grows older. And he will need to be closely followed by a Children’s pediatric cardiologist, who will determine care going forward.

Q: What causes ToF/PA?
A:
The heart starts to form during the first eight weeks of fetal development. In ToF, during this development period the heart doesn’t develop properly. It usually occurs sporadically (by chance), with no clear reason for its development.

Q: If my child has ToF/PA, what should I ask my doctor?
A:
Some of the questions you may want to ask include:

  • What tests will you perform to further diagnose my child?
  • What actions might you take after you reach a diagnosis?
  • What are the possible complications from testing and treatment?           
  • Will there be long-term effects or restrictions?
  • Will my child need additional care as he grows?
  • What is your experience treating babies with this condition?
  • What can we do at home?

Q: How is ToF/PA usually diagnosed?
A:
For most patients, doctors use an EKG (electrocardiogram), cardiac ultrasound (echocardiogram) and cardiac catheterization (sometimes multiple) with angiography to diagnose ToF/PA.

Q: What will happen after surgery for ToF/PA?
A:
After ToF/PA repair, the baby will be taken to Children’s Cardiac Intensive Care Unit (CICU), where his vital signs and other factors are very closely monitored. In most cases, the CICU stay is for one or two days, followed by a few days’ recovery on “8E,” the unit where patients with cardiac conditions are followed. Post-operative care varies greatly, based partly on the age of the child.

When your child is ready to go home, we’ll give you any home-care information that you will need. And after your child’s discharge from Children’s, his cardiologist and pediatrician will provide follow-up monitoring and care.

Q: What is Children’s experience treating congenital heart defects?
A:
Children’s surgeons treat some of the most complex pediatric heart conditions in the world, with overall success rates among the highest in the nation among large pediatric cardiac centers.

Our experts have pioneered some of medical science’s most advanced heart treatments, now in use around the globe.

Q: What heart research and innovations are coming from Children’s?
A:
Children’s is pursuing many areas of research into the cardiovascular system. For example, Children’s was one of a small number of centers to test and first clinically use a new type of valve that can be placed into the heart using a catheter (thus obviating the need to open the chest or do open heart surgery). This valve is very useful for some older patients who’ve developed significant pulmonary regurgitation after repair of ToF/PA.


Learn more about Children’s cardiac surgery research initiatives and Children’s current projects in cardiology research.

Q: Where can my child find care and support when he grows up?
A:
The Boston Adult Congenital Heart and Pulmonary Hypertension Service (BACH) provides long-term inpatient and outpatient care and advanced therapeutic options for patients with congenital heart disease and pulmonary hypertension as they reach and progress through adulthood.

BACH is an international center for excellence, with physicians and services from Children’s, Brigham and Women’s Hospital and Beth Israel Deaconess Medical Center. The center promotes and supports clinical and scientific research for the advancement of care of these patients, and is a leader in the education of providers caring for this unique population.

The Adult Congenital Heart Association (ACHA) is a national not-for-profit organization dedicated to improving the quality of life—and extending the life—of adults with congenital heart defects. The organization serves and supports many of the adults with congenital heart defects (now thought to number as many as one million), their families and the medical community, as well as conducting research and providing advocacy, outreach and education. 

Causes

Most often, this heart defect occurs sporadically (by chance), with no clear reason for its development, due to the abnormal development of the heart during the first eight weeks of fetal growth. However, a genetic link has been found in some severe cases.

Signs and symptoms

Signs and symptoms of ToF/PA usually appear shortly after a baby is born, when the maternal source of oxygen (from the placenta) is removed. The principal sign is cyanosis (blue color to the skin, lips and nail beds) due to large amounts of oxygen-poor (blue) blood flowing to the body.  Sometimes this condition becomes apparent only at an older age.

When to seek medical advice

Most of the time, this defect is detected by your child’s doctor soon after birth. However, call your health care provider immediately if your baby or child has a bluish color, becomes tired with feeding, or has poor weight gain.

Questions to ask your doctor

After your child is diagnosed with ToF/PA, you may feel overwhelmed with information. It can be easy to lose track of the questions that occur to you. Lots of parents find it helpful to jot down questions as they arise—that way, when you talk to your child’s doctors, you can be sure that all of your concerns are addressed.

Some of the questions you may want to ask include:

  • What tests will you perform to further diagnose my child?
  • What actions might you take after you reach a diagnosis?
  • What are the possible complications from testing and treatment?           
  • Will there be long-term effects or restrictions?
  • Will my child need additional care as he grows?
  • What is your experience treating babies with this condition?
  • What can we do at home?

Who’s at risk

Congenital heart defects usually occur sporadically (by chance), with no clear reason for their development. So, it’s difficult to predict who’s at risk. But in ToF, familial cases have been reported, and a genetic link has been confirmed in some cases.

Parents who have a child with a ToF (or other congenital heart defect) have a slightly greater chance of having a second child with a heart defect, and a fetal ultrasound during the second trimester of pregnancy is recommended.

Complications

Children who have surgery to repair ToF/PA generally do very well. But many types of complications can occur, some of which include bleeding, arrhythmias, blood clots, leaky valves, or the need for early catheterization or re-operation.

Long-term outlook

While the outlook varies from child to child, open heart surgery at Children’s has among the highest success rates in the United States among large pediatric cardiac centers, and the long-term outlook for the great majority of children is excellent.

Your child may need multiple operations or catheterizations as he grows older. And he’ll need to be followed by a Children’s pediatric cardiologist, who will determine care going forward.

For teens

If you’re a teen with a congenital heart defect, you have a lot to cope with. Besides the typical issues any teenager faces—from social acceptance to body changes and more—you’ll also have to deal with medical appointments and procedures, some possible restrictions on your physical activities, feeling different and assuming a lot of personal responsibility for maintaining your own good health.

If you feel down or anxious through this important time in your transition to adulthood, speak to your doctor, counselor or parents—they’re all on your team, and they want to help.

Learn about Children’s many resources for teens, including our Teen Advisory Committee.

For adults

If you were treated for congenital heart disease as a child, you’re probably being followed by your cardiologist, since complications from early heart disease can arise in adulthood.

You may need lifelong monitoring and medication, since you could be at some risk for arrhythmias, leaky valves and other heart problems. Going forward, your cardiologist will advise you on activity levels, pregnancy issues and certain lifestyle choices.

Children’s can help adults with congenital heart defects. Many adults who were patients at Children’s as babies or children continue to be monitored by the clinicians who’ve followed them since childhood.

In addition, our Boston Adult Congenital Heart and Pulmonary Hypertension Service (BACH) provides long-term inpatient and outpatient care and advanced therapeutic options for patients with congenital heart disease and pulmonary hypertension as they reach and progress through adulthood.

BACH is an international center for excellence, with physicians and services from Children’s, Brigham and Women’s Hospital and Beth Israel Deaconess Medical Center. The center promotes and supports clinical and scientific research for the advancement of care of these patients, and is a leader in the education of providers caring for this unique population.

Prevention

Congenital heart defects usually occur sporadically (by chance), with no clear reason for their development. ToF may be prevented if a pregnant woman refrains from alcohol or drug abuse. If you’re taking anti-seizure medicine and are pregnant or planning to become pregnant, consult your doctor, since medications of this kind have been associated with this condition.

ToF/PA glossary

  • aorta: one of the heart’s two great arteries. In a normal heart, the aorta arises from the left ventricle and carries oxygen-rich blood out to the body.
  • cardiac catheterization: an invasive diagnostic procedure performed under sedation to obtain detailed visual information and measurements about the structures inside the baby’s heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta. Certain therapeutic procedures can be performed at cath, e.g., dilating blood vessels to make them larger.
  • cardiac/cardio-: pertaining to the heart
  • cardiac magnetic resonance imaging (MRI): a non-invasive diagnostic tool using 3-D imaging technology produced by magnets to accurately determine the blood flow and functioning of your child's heart
  • cardiac surgery: a surgical procedure performed on the heart or one of the blood vessels connected to the heart
  • cardiac surgeon: a doctor who performs surgery on the heart. A pediatric cardiac surgeon performs surgery on the hearts of infants and children.
  • cardiologist: a doctor who diagnoses and treats heart problems non-surgically. A pediatric cardiologist treats infants, children and some adults with heart problems.
  • chest CT scan: a non-invasive procedure that uses x-ray equipment and powerful computers to create detailed, cross-sectional images of your child's heart and chest anatomy
  • chest x-ray: a diagnostic tool to evaluate the size and spatial relationships of the heart within the child’s chest
  • cyanosis (cyanotic): blue color of skin, lips and nailbeds caused by a reduction in the amount of oxygen-rich (red) blood circulating in baby’s bloodstream
  • congenital heart defect: heart defect present at birth. The heart usually starts to form in the first eight weeks of fetal development. It’s thought that most congenital heart defects develop during this period.
  • diagnosis: medical determination of illness or disease based on history, physical examinations and advanced technology diagnostic testing tools
  • ductus arteriosus: the prenatal connection between the aorta and the pulmonary artery, which usually closes shortly after birth.
  • echocardiogram (echo, cardiac ultrasound): a diagnostic tool that evaluates the structure and function of the heart using sound waves that produce a moving picture of your child’s heart and heart valves; can be used to understand flow in the different chambers and to estimate pressures
  • electrocardiogram (ECG, EKG): a diagnostic tool that evaluates the electrical activity of your child’s heart. An EKG is usually the initial test for evaluating the causes of symptoms and detecting heart abnormalities, including ToF/PA.
  • homograft:a specially prepared pulmonary artery taken from a person who has died
  • hypertrophy: abnormal enlargement
  • IV: intravenous, into the vein; one method of delivering medication
  • neonatologist: a doctor who specializes in illnesses affecting newborns, both premature and full-term
  • pericardium: the thin but tough leather-like sac that surrounds the heart
  • pulmonary artery: one of the heart’s two great arteries, which normally arises from the right ventricle and carries oxygen-poor blood to the lungs, where it receives oxygen
  • pulmonary atresia: a congenital heart defect in which the pulmonary valve is absent or doesn’t open and oxygen-poor blood can’t get through the pulmonary artery to the lungs to pick up oxygen
  • pulmonary valve: one of the four valves in the heart, between the right ventricle and the pulmonary artery; allows blood to flow one way to the lungs to pick up oxygen
  • pulse oximetry: a non-invasive test to measure the amount of oxygen in the blood
  • sporadic: occurring by chance, occasionally, not inherited
  • symptoms: the presenting reasons why a child needs medical attention. Characteristics such as onset, quality, triggers and severity help diagnosticians to determine a disease, or to decide which testing is needed to determine the disease.
  •  ventricular septal defect (VSD): a congenital (present at birth) heart defect associated with ToF in which there’s an opening in the tissue wall (septum) that divides the two lower chambers of the heart (right and left ventricles)

For a more complete list of cardiovascular terms, visit our Cardiovascular Glossary.

For in-depth visual information on several of the conditions, diagnostic tools and procedures described above, visit our cardiovascular Multimedia Library.


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- Sandra L. Fenwick, President and CEO

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