Single Ventricle Defects

Updated:Mar 26,2014

What are they?

Rare disorders affecting one lower chamber of the heart. The chamber may be smaller, underdeveloped, or missing a valve.

Hypoplastic Left Heart Syndrome (HLHS) - An underdeveloped left side of the heart. The aorta and left ventricle are too small and the holes in the artery and septum did not properly mature and close.

Pulmonary Atresia/Intact Ventricular Septum - The pulmonary valve does not exist, and the only blood receiving oxygen is the blood that is diverted to the lungs through openings that normally close during development.

Tricuspid Atresia - There is no tricuspid valve in the heart so blood cannot flow from the body into the heart in the normal way. The blood is not being properly refilled with oxygen it does not complete the normal cycle of body -heart –lungs- heart - body.

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Hypoplastic Left Heart Syndrome

What is it?

In hypoplastic left heart syndrome (HLHS), the heart's left side — including the aorta, aortic valve, left ventricle and mitral valve — is underdeveloped.
 

What causes it?

In most children, the cause isn't known. Some children can have other heart defects along with HLHS.
 

How does it affect the heart?

In HLHS, blood returning from the lungs must flow through an opening in the wall between the atria (atrial septal defect). The right ventricle pumps the blood into the pulmonary artery and blood reaches the aorta through a patent ductus arteriosus (see diagram).
 

Medical Illustration Of Heart

How does the defect affect my child?

The baby often seems normal at birth but comes to medical attention within a few days of birth as the ductus closes. The baby may appear ashen, have rapid and difficult breathing and have difficulty feeding. This heart defect is usually fatal within the first days or month of life unless it's treated.
 

What can be done about the defect?

This defect isn't correctable, but some babies can be treated with a series of operations, or heart transplantation. Until an operation is performed, the ductus is kept open by intravenous medication. Because these operations are complex and need to be adapted for each child, it's necessary to discuss all the medical and surgical options with your child's doctor.
 

If you and your child's doctor agree that surgery should be performed, it will be done in several stages. The first stage, referred to as the Norwood procedure, allows the right ventricle to pump blood to both the lungs and the body without the need for the ductus to be kept open. Blood is directed to the lungs through either a Blalock-Taussig (arrow on inserted picture) or Sano shunt. The Norwood procedure must be performed soon after birth. The second stage (bidirectional Glenn or hemi-Fontan) is usually performed between 4 and 12 months and the third stage (lateral tunnel Fontan or extracardiac Fontan) is usually performed between 18 months and 3 years.
 

              Medical Illustration Of Heart                                            Medical Illustration Of Heart

 

Medical Illustration Of Heart                                  Medical Illustration Of Heart


These operations create a connection between the veins returning low-oxygen (bluish) blood to the heart and the pulmonary artery. The goal is to allow the right ventricle to pump only oxygenated blood to the body and to prevent or reduce cyanosis (lower than normal blood oxygen levels). Some infants require several intermediate operations to achieve this.
 

Some doctors recommend heart transplantation to treat HLHS. Although it can provide the infant with a heart that has normal structure, the infant will require life-long medications to prevent rejection. Many other transplant-related problems can develop, and these should be discussed with your child's doctor.
 

What activities can my child do?

Children with HLHS may be advised to limit their physical activities to their own endurance. Generally, many competitive sports pose greater risk. Your child's pediatric cardiologist will help determine the proper level of activity.
 

What will my child need in the future?

Children with HLHS require lifelong follow-up by a cardiologist for repeated checks of how their heart is working. Virtually all children with HLHS will require heart medicines, heart catheterization and additional surgery.
 

What about preventing endocarditis?

Children with HLHS are at increased risk for developing endocarditis. Ask your pediatric cardiologist about your child's need to take antibiotics before certain dental procedures to help prevent endocarditis. See the section on Endocarditis for more information.
 

Download and print a PDF version of this information
Congenital Heart Defect ID Card


Síndrome del Corazón Izquierdo Hipoplástico
Soplo normal o funcional del corazón


Pulmonary Atresia

What is it?
In pulmonary atresia, no pulmonary valve exists. Blood can't flow from the right ventricle into the pulmonary artery and on to the lungs. The right ventricle and tricuspid valve are often poorly developed.Medical Illustration Of Heart

 

What causes it?

In most children, the cause isn't known. Some children can have other heart defects along with pulmonary atresia. (Children with tetralogy of Fallot who also have pulmonary atresia may have treatment similar to others with tetralogy of Fallot.)
 

How does it affect the heart?

An opening in the atrial septum lets blood exit the right atrium, so low-oxygen (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 infant appears blue (cyanotic) because there's less oxygen in the blood. The only source of lung blood flow is the patent ductus arteriosus (PDA), an open passageway between the pulmonary artery and the aorta.
 

How does pulmonary atresia affect my child?

If the PDA narrows or closes, the lung blood flow is reduced to critically low levels. This can cause very severe cyanosis. Symptoms may develop soon after birth.
 

What can be done about the defect?

Temporary treatment includes a drug to keep the PDA from closing. A surgeon can create a shunt between the aorta and the pulmonary artery that may 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 some children, abnormal channels (sinusoids) form between the coronary arteries and the right ventricle. These sinusoids can also limit the type of surgery a child can have. In children where the pulmonary artery and right ventricle are more normal in size, open-heart surgery may help the heart work better.
 

If the right ventricle stays too small to be a good pumping chamber, the surgeon can connect the body veins directly to the pulmonary arteries. The atrial defect also can be closed to relieve the cyanosis. These surgeries are called the Glenn and Fontan procedures.
 

What activities can my child do?

Children with pulmonary atresia may be advised to limit their physical activities to their own endurance. Some competitive sports may pose greater risk. Your child's pediatric cardiologist will help determine the proper level of activity.
 

What will my child need in the future?

Children with pulmonary atresia need regular follow-up with a pediatric cardiologist and, once they reach adulthood, lifelong regular follow-up with a cardiologist who's had special training in congenital heart defects. Some children may need medicines, heart catheterization or additional surgery.
 

What about preventing endocarditis?

Children with pulmonary atresia are at increased risk for developing endocarditis. Ask your pediatric cardiologist about your child's need to take antibiotics before certain dental procedures to help prevent endocarditis. See the section on Endocarditis for more information.
 

Download and print a PDF version of this information
Congenital Heart Defect ID Card

Atresia pulmonar
Como funciona el corazón sano


Tricuspid Atresia

What is it?

In this condition, there's no tricuspid valve so blood can't 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 (atrial septal defect) and usually an opening in the wall between the two ventricles (ventricular septal defect). As a result, the low-oxygen (bluish) blood that returns from the body veins to the right atrium flows through the atrial septal defect and into the left atrium. There it mixes with oxygen-rich (red) blood from the lungs. Most of this partially oxygenated blood goes from the left ventricle into the aorta and on to the body. A smaller-than-normal amount flows through the ventricular septal defect into the small right ventricle, through the pulmonary artery, and back to the lungs. Because of this abnormal circulation, the child looks blue (cyanotic).

Medical Illustration Of Heart

What can be done to treat it?

Often it's necessary to do a surgical procedure, called a shunt, to increase blood flow to the lungs. This improves the cyanosis. Some children with tricuspid atresia have too much blood flowing to the lungs. They may need a different type of surgery, called pulmonary artery banding, to decrease blood flow to the lungs. This is important to protect the lung blood vessels.
 

Medical Illustration Of Heart            Medical Illustration Of Heart


Can it be repaired?

Most children with tricuspid atresia can have surgery to allow their hearts to work more like normal. Connections are created between the body veins and the lung (pulmonary) arteries. This is usually done in two stages. First, the large vein from the upper half of the body (the superior vena cava) is connected to the lung arteries in a procedure called a Bidirectional Glenn Operation.
 

Later, the large vein from the lower half of the body (the inferior vena cava,) as well as the veins from the liver, are connected to the lung arteries in a surgery called a Fontan Operation. Sometimes, at the time of the Fontan surgery, an opening is purposely left between the bluish (low-oxygen) and red (high-oxygen) sides of the blood flows. The Fontan operation may eliminate or greatly improve the cyanosis but, without a right ventricle that works normally, the heart doesn't work like a normal heart, which has two pumps. The Fontan procedure can be performed using a tube that goes around the heart as shown in the picture or with a path (baffle) that goes inside the heart. Both types of Fontan operations route the blue blood from the lower half of the body and liver to the lungs.

 

            Medical Illustration Of Heart                       Medical Illustration Of Heart


What will my child need in the future?

Children with tricuspid atresia require lifelong follow-up by a cardiologist for repeated checks of how their heart is working.
 

What about preventing endocarditis?

Children with tricuspid atresia are at increased risk for developing endocarditis. Ask your pediatric cardiologist about your child's need to take antibiotics before certain dental procedures to help prevent endocarditis. See the section on Endocarditis for more information.
 

Download and print a PDF version of this information

Congenital Heart Defect ID Card
 

Atresia Tricúspide
Soplo normal o funcional del corazón


Congenital Heart Defects

Web Booklets on Congenital Heart Defects

blue papersThese online publications describe many defects and the procedures used to repair them. This information is designed so that you can customize it to your own needs. It’s organized so that you can print out the sections that relate to you or your child’s defect and concerns.

CHD Personal Stories

personal stories

These touching stories from parents and young survivors affected by congenital heart defects provide inspiration and hope.