Single ventricle defects

It’s natural for you to be concerned right now about your child’s health—the diagnosis of a single ventricle defect can be overwhelming. But you can rest assured that at Children’s Hospital Boston, your child is in expert hands.

Consistently ranked among the top pediatric hospitals in the United States, Children’s ishome to the world's most extensive pediatric hospital research enterprise; and we partner with elite health care and biotech organizations around the globe. But as specialists in innovative, family-centered care, our physicians never forget that your child is precious, and not just a patient.
 

What are single ventricle defects?

Normally, the heart has a right and left ventricle that serve as the heart's pumping chambers. The right ventricle normally pumps blue blood (without oxygen) out of the heart through the pulmonary artery to the lungs for oxygen and the left ventricle normally pumps red blood (with oxygen) through the aorta out of the heart to the body.

“Single ventricle defect” is a general term used to describe several very different complex congenital (present at birth) heart defects that share the same problem: the heart has only one functional ventricle.

• The defect occurs when the heart's right ventricle is undeveloped and doesn't perform its job of pumping blood to the lungs.
• Both atria connect to the single ventricle either through a single valve (called a common-inlet ventricle) or separate valves (called a double-inlet ventricle).
• Sometimes it’s the left ventricle that’s underdeveloped and there’s a single right ventricle, but this is rare.

The following congenital heart defects are considered single ventricle defects:

• tricuspid atresia (TA)
  • TA is the abnormal development of the tricuspid valve, which prevents blood from passing from the right atrium to the right ventricle, as it should.

• hypoplastic left heart syndrome (HLHS)
  • A defect in which most of the structures on the left side of the heart, including the left ventricle that pumps blood out of the body, are small and underdeveloped.

• mitral valve atresia (often associated with HLHS)
  • The mitral valve does not develop properly, and blood from the left atrium doesn’t flow to the left ventricle.
  • The left ventricle becomes small and underdeveloped.

• double outlet right ventricle (DORV)
  • Normally, a ventricle has just one outlet—for the left ventricle, it’s the aorta; for the right ventricle, it’s the pulmonary artery that leads to the lungs. In this defect the right ventricle has an outlet to both the aorta and the pulmonary artery.
  • There are usually other heart defects present.
  • When there’s an underdeveloped left ventricle, a DORV is considered a single ventricle defect.

• pulmonary atresia with intact ventricular septum (PA/IVS)
  • Some forms of pulmonary atresia with a very small right ventricle will need a single-ventricle-defect approach because the right ventricle is too small to do its job.

What causes single ventricle defects?

The heart forms during the first eight weeks of fetal development. It’s at this time that defects that result in single ventricle emerge. Most of the time, these kinds of heart defects occur sporadically (by chance), which no clear reason for their development.

 Some congenital heart defects may have a genetic link—occurring due to a defect in a gene, a chromosome abnormality or environmental exposure—causing heart problems to occur more frequently in certain families.

 It’s important for parents to understand that you’ve done nothing to cause your baby’s tricuspid atresia and its accompanying defects. Nothing you have ingested or have been exposed to environmentally has been definitively be linked to having a baby with a single ventricle defect.

Why are single ventricle defects a concern?

Single ventricle heart defects can cause children to become cyanotic (blue color), since a mixture of oxygen-poor (blue) and oxygen-rich (red) blood vessels leaves the heart and goes to the body. Just how much oxygen or how little oxygen depends on the type, location and severity of the defect. Some children will only be mildly cyanotic, while others won’t have enough oxygen in the blood to meet the body's needs and will need early treatment.

What are the symptoms of single ventricle defects?

Symptoms are usually noted shortly after birth. The most common symptoms of single ventricular defects include:

• blue color of the skin, lips, and nailbeds (cyanosis)
• rapid breathing
• labored breathing
• rapid heart rate
• cool, clammy skin

How do you diagnose single ventricle defects?

Cyanosis is the major indication that there is a problem with your newborn. Your child's physician may have also heard a heart murmur during a physical exam. (A heart murmur is a noise caused by the turbulence of blood flowing through the openings that allow the blood to mix.) Your doctor will probably refer you to a pediatric cardiologist and/or a neonatologist for further evaluation.

Other tests are usually needed to help with the diagnosis, and may include:

• chest x-ray
• electrocardiogram (EKG)
• cardiac ultrasound (echocardiogram)
• cardiac catheterization
• cardiac MRI (magnetic resonance imaging)

These tests may be looking for:

• poor perfusion (circulation to the body’s tissues)
• blood pressure differences between the right arm and lower extremities
• abnormal heart sounds

How do you treat single ventricle defects?

The treatments for single ventricle defects vary, depending mostly on the amount of mixing of blood, and how much blood is being pumped through the lungs. This varies greatly from defect to defect, but always involves surgery or surgeries.

• pulmonary artery band
  • implanted onto the main pulmonary artery in order to restrict blood flow to the lungs
  • mesh-type device that wraps around the main pulmonary artery and is systematically closed until pulmonary pressures are normal
  • often recommended for babies with too much blood flow to the lungs
  • can be removed at any time

• shunt
  • surgical connection between an artery from the aorta to the pulmonary artery
  • increases blood flow to the lungs
  • recommended for babies with too little blood flow to the lungs (blue babies)

Other procedures may accompany these treatments, depending on the anatomy of the defect. Common to all is that these procedures are temporary in order to stabilize the baby’s circulation. Additional procedures are usually necessary as the child grows.

For more detail, see Treatment and care.

Will my child be OK?

Open heart surgery at Children’s has among the highest success rates in the United States among large pediatric cardiac centers. With our advanced surgical techniques and timely, family-centered care, the likelihood is very good that your child will undergo successful surgery.

Note: Infants who’ve had initial surgery for a single ventricle defect are typically enrolled in Children’s Home Monitoring Program between the baby’s Stage I and Stage II operations in the Fontan sequence. For more, see “Children’s Home Monitoring Program for your child” in Treatment & care.

How common or rare are single ventricle defects?

Single ventricle defects are rare, occurring in just five out of every 100,000 live births. Single ventricle defects occur equally in boys and girls, and usually become apparent within the first month of life. Signs of a severe single ventricle defect can be apparent at birth (blue baby syndrome) or shortly thereafter.

What about later in life?

Your cardiologist will help you create a long-term care program as your baby matures into childhood, the teen years and even adulthood. Most people who have had congenital heart disease repair will have an ongoing relationship with their cardiologist since they will always be at some risk for arrhythmias, infections, heart failure or stroke. We will treat complications and will advise on daily-life issues such as exercise and activity levels, nutrition and precautions related to pregnancy.

Where can my child find care and support when he grows up?

• 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 (thought at this time to be as many as one million), their families and the medical community, as well as conducting research and providing advocacy, outreach and education.

FAQ
 

Q: What is a single ventricle defect?
A: “Single ventricle defect” is a general, non-specific term used to describe several congenital heart defects that differ from each other, but that share the same problem: The heart has only one adequate-sized functional pumping chamber (ventricle).

As a result, one ventricle is underdeveloped (hypoplastic) or missing (atretic) and can’t adequately pump blood to the lungs. The heart defect causes children to be cyanotic (blue), since a mixture of oxygen-poor (blue) and oxygen-rich (red) blood leaves the heart and goes to the body.

 
Q: If my child has a single ventricle defect, will he be OK?
A: Open heart surgery at Children’s Hospital Boston has among the highest success rates in the United States among large pediatric cardiac centers. With our advanced surgical techniques and timely, family-centered care, the likelihood is very good thatyour child will undergo successful surgeries for single ventricle defects.                    
 

Q: How does Children’s treat single ventricle defects?
A: The skilled surgeons at Children’s virtually always treat single ventricle defects with a series of operations performed in the baby’s first few years. The goal of these surgeries is to re-route blood flow so that enough oxygen is added to the baby’s bloodstream to meet his body’s needs.
 

Q: What are the symptoms of a single ventricle defect?
A: Many babies with a single ventricle defect show symptoms on the day they are born or shortly thereafter. Other babies usually show symptoms in the first month of life. These can include:

• blue color of the skin, lips, and nailbeds (cyanosis)
• rapid breathing
• labored breathing
• rapid heart rate
• cool, clammy skin
   

Q: If my child has a single ventricle defect, what should I ask my Children’s doctor?
A: Some of the questions you may want to ask include:

• What tests will you perform to further diagnose my child?
• Which single ventricle defect does he have? What are its characteristics?
• Does he need surgery? How long will the surgery take? How long for him to recover?
• Will he need additional surgeries during early childhood?
• Will my child be OK if he has congenital heart disease?
• Will there be restrictions on my child’s activities in the future?
• Will there be long-term health effects? Can this recur?
• Will there be continuing risks?
• What can we do at home?
   

Q: When are single ventricle defects usually diagnosed, and how?
A: A single ventricle defect like HLHS can sometimes be detected on a routine prenatal ultrasound. Many babies with a single ventricle defect show symptoms on the day they’re born or shortly thereafter. Other babies usually show symptoms in the month of life.

If your newborn baby was born with a bluish tint to his skin, or if your young child is experiencing symptoms, your pediatrician will refer you to a pediatric cardiologist, who will perform a physical exam.

Your Children’s cardiologist will detect a heart murmur, measure blood oxygen levels (non-invasively) and order diagnostic testing, which could include EKG, cardiac ultrasound, cardiac MRI, cardiac catheterization or chest x-ray.
 

Q: What should we do at home after surgery for a single ventricle defect?
A: Consult your child’s cardiologist for guidance on follow-up care—including:

• wound care while your baby is healing
• a nutritional program to encourage weight gain
• an oral hygiene program to prevent infection
• an appropriate exercise regimen to build body mass and achieve fitness

As your baby recovers and grows, be sure to follow a program of regular well-baby/well-child checkups.
 

Q: What is the long-term outlook for children who’ve had a single ventricle defect?
A: Surgical techniques for single ventricle defects are continually being refined, and long-term outcomes are continually improving. Still, patients will need lifelong monitoring and medication, since they’ll always be at some risk for arrhythmias, blood clots, infections, heart failure or stroke.
 

Q: What causes single ventricle defects?
A: Most often this heart defect occurs sporadically (by chance), with no clear reason for its development. It’s important for parents to understand that you’ve done nothing to cause your baby’s single ventricle defect. Nothing you’ve ingested or have been exposed to environmentally has been definitively be linked to having a baby with a single ventricle defect.
 

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 approaching 98 percent—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. Children’s is the only major pediatric heart center in the world performing fetal heart interventions in volume for certain congenital defects.
 

Q: What heart research and innovations are coming from Children’s?
A: A significant amount of the important cardiac research being conducted at Children’s Hospital Boston aims to refine and advance the open heart surgery and catheterization procedures that treat congenital heart defects in newborns and young children—including single ventricle defects.

Read more about Children’s cardiac research initiatives and projects in cardiology research.
 

Causes
 

The heart forms during the first eight weeks of fetal development. It’s at this time that defects that result in single ventricle emerge. Most of the time, these kinds of heart defects occur sporadically (by chance), which no clear reason for their development.

Some congenital heart defects may have a genetic link—occurring due to a defect in a gene, a chromosome abnormality or environmental exposure—causing heart problems to occur more frequently in certain families.

It’s important for parents to understand that you’ve done nothing to cause your baby’s single ventricle defect. Nothing you’ve ingested or have been exposed to environmentally has been definitively be linked to having a baby with a single ventricle defect.

Symptoms
 

Many babies with a single ventricle defect show symptoms on the day they are born or shortly thereafter. Other babies usually show symptoms in the first month of life. These can include:

• blue color of the skin, lips, and nailbeds (cyanosis)
• rapid breathing
• labored breathing
• rapid heart rate
• cool, clammy skin

If your child has any of these symptoms, your pediatrician will probably refer you to a pediatric cardiologist for testing, diagnosis and a determination of treatment.

When to seek medical advice
 

Call your health care provider immediately if your baby or child is having difficulty breathing or is breathing rapidly, has a bluish color, tires too easily or is uninterested in eating.

Questions to ask your doctor
 

If your child is diagnosed with a single ventricle defect, you may feel overwhelmed with information. It’s easy to lose track of the questions that occur to you—so lots of parents find it helpful to jot down questions as they arise. This 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?
• Which single ventricle defect does he have? What are its characteristics?
• Does he need surgery? How long will the surgery take? How long for him to recover?
• Will he need additional surgeries during early childhood?
• Will my child be OK if he has congenital heart disease?
• Will there be restrictions on my child’s activities in the future?
• Will there be long-term health effects? Can this recur?
• Will there be continuing risks?
• 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. Familial cases have been reported, but no genetic link has been confirmed. Single ventricle defects occur equally in boys and girls. In general, if you have a child with a congenital cardiac defect, the chance of your having another child with a defect is about 2 to 3 percent.

Complications
 

The first children who underwent the staged surgical repairs for tricuspid atresia and some other single ventricle defects are now in their 20s and largely doing well. However, complications can occur, including arrhythmias, blood clots, infections within the heart (endocarditis), easy tiring and loss of protein from the digestive tract. As your child grows, it’s important for him to be monitored closely by his cardiologist.

Long-term outlook
 

Surgical techniques for single ventricle defects are continually being refined, and long-term outcomes are continually improving. Even so, patients will need lifelong monitoring and medication, since they will always be at some risk for arrhythmias, blood clots, infections, heart failure or stroke.

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 delay of your natural wish for independence … feeling different … and assuming a lot of personal responsibility for maintaining your own good health.

If you feel overwhelmed, depressed or anxious through this important time in your transition to adulthood, speak to your doctor or counselor to get help.

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’ll continue to be at some risk for arrhythmias, blood clots, infections, heart failure or stroke. Going forward, your cardiologist will also advise you on activity levels, pregnancy issues and certain lifestyle choices.

Fortunately, Children’s can help adults with congenital heart defects. Many adults who were patients as babies or children continue to be monitored by the clinicians who have 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.

What you can do at home
 

Consult your child’s cardiologist for guidance on follow-up care—including:

• wound care while your baby is healing
• a nutritional program to encourage weight gain
• an oral hygiene program to prevent infection
• an appropriate exercise regimen to build body mass and achieve fitness

As your baby recovers and grows, be sure to follow a program of regular well-baby/well-child checkups.

 

Prevention
 

It’s important to understand that as parents, you’ve done nothing to cause your child’s single ventricle defect, and there are no precautions you could have taken to prevent it. Congenital heart defects usually occur sporadically (by chance), with no clear reason for their development.

Single ventricle defect 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.
   
• bi-directional Glenn: surgical procedure that frequently replaces the Blalock-Taussig shunt with another connection to the pulmonary artery to provide a path for blue blood to go out to the lungs. The superior vena cava is surgically connected to the right pulmonary artery to direct blood from the upper part of the body to the lungs to receive oxygen. This is the second procedure of the Fontan Sequence.
   
• Blalock-Taussig Shunt: a surgical procedure to create a pathway for blood to reach the lungs. A shunt (tube) may be inserted between the aorta or one of its branches and pulmonary artery to increase blood flow. This is frequently the first procedure of the Fontan Sequence.
   
• 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 in the pulmonary artery and aorta.
   
• 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: surgical procedure performed on the heart or one of the blood vessels connected to the heart
   
• cardiac surgeon: doctor who performs surgery on the heart. A pediatric cardiac surgeon performs surgery on the hearts of infants and children.
   
• cardiologist: doctor who diagnoses and treats heart problems non-surgically. A pediatric cardiologist treats infants, children and some adults with heart problems.
   
• The Center for Families at Children’s: dedicated to helping families find the information, services and resources they need to understand their child’s medical condition and take part in their care
   
• chest x-ray: a diagnostic tool chest to evaluate the size and spatial relationships of the heart within the child’s chest, as well as the presence of TA and its associated defects
   
• 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 is 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
   
• double outlet right ventricle (DORV): a congenital heart defect in whichthe right ventricle has an outlet to both the aorta and the pulmonary artery. When there’s an underdeveloped left ventricle, a DORV is considered a single ventricle defect.
   
• 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. The ultrasound 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 single ventricle defects.
   
• Fontan sequence: a series of three operations performed on children who have just one full-sized functioning ventricle (a single ventricle defect). The Fontan operations are usually performed at intervals starting within days or months after birth and ending at a few years of age. The Fontan operation is the third procedure in the Fontan Sequence.
   
• hypoplastic left heart syndrome (HLHS): a single ventricle defect in which most of the structures on the left side of the heart, including the left ventricle that pumps blood out of the body, are small and underdeveloped.
   
• mitral valve atresia: a single ventricle defect, often associated with HLHS, in whichthe mitral valve doesn’t develop properly, and blood from the left atrium doesn’t flow to the left ventricle. As a result, the left ventricle becomes small and underdeveloped.
   
• neonatologist: a doctor who specializes in illnesses affecting newborns, both premature and full-term
   
• Norwood procedure: for HLHS, the first stage surgery, usually performed in the first week of the baby’s life. Developed at Children’s Hospital Boston, the procedure connects the right ventricle to the aorta so that its flow will be delivered to the body through branches of the aorta. Two alternatives to the Norwood procedure are sometimes performed based on surgical preference, the child’s size and the anatomy of the defects.
   
• pediatric cardiologist: a doctor who specializes in the diagnosis and medical management of congenital heart defects, as well as heart problems that may develop later in childhood
   
• 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 artery banding (PAB): a repair in which a band is secured around the pulmonary artery to limit blood flow to the lungs
   
• shunt: an artificial connection of blood vessels in order to redirect blood to the lungs in children with inadequate flow for oxygenation
   
• single left ventricle (common-inlet ventricle, double-inlet ventricle): This defect occurs when the heart's right ventricle is undeveloped and doesn't perform its job of pumping blood to the lungs. Both atria connect to the single ventricle either through a single valve (called a common-inlet ventricle) or separate valves (called a double-inlet ventricle).
   
• single ventricle defect (SVD): one of several congenital (present at birth) heart defects in which the heart has only one fully functioning ventricle.
   
• sporadic: occurring by chance, occasionally, not inherited
   
• symptoms: the presenting reasons why a child needs medical attention. A symptom’s 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.
   
• tricuspid atresia: a rare congenital (present at birth) heart defect in which the tricuspid valve is absent or blocked off, resulting in a small or absent right ventricle that cannot adequately pump blood to the lungs; usually considered a single ventricle defect.
   

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 Children’s cardiovascular Multimedia Library.