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Heterotaxy Heart Defects

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News that your child has heterotaxy syndrome can leave you reeling with questions, confusion and fear. Fortunately, the Heart Center at Cook Children's is one of the few pediatric cardiology centers in the U.S. with experience in this extremely rare congenital abnormality. Our caring team has the knowledge and the compassion to help you and your child through the challenges of this very complex condition.

What it is

The dictionary defines heterotaxy as an irregular arrangement of parts. Though heterotaxy syndrome is extremely rare–in the U.S., about one in every 250,000 children are born with it–it is the cause of some of the most complex and complicated heart defects. Heterotaxy is a disorder that results in certain organs forming on the wrong side of the body, most typically the heart, lungs, kidneys, liver, stomach, intestines and spleen. Sometimes organs may also be facing in the wrong direction, may be divided into multiple sections (the spleen sometimes divides into smaller spleens) and some organs may even be missing. In normal development, organs that come in pairs, such as lungs and kidneys look alike but they are not identical. Instead, these organs are each designed to provide specific functions on one side of the body (left or right). In heterotaxy, the organs may exactly mirror one another. This results in organs that cannot function correctly (much like putting your shoes on the wrong feet–they look alike but they do not function the same).

Heterotaxy is divided into two categories: asplenia syndrome, also called right atrial isomerism, and polysplenia syndrome, or left atrial isomerism. In its simplest term, isomerism means mirror imaging.

Asplenia– if your child is diagnosed with asplenia it means that his or her heart has multiple defects, some of which may be:

  • Holes in the walls of the heart – septal defects
  • Heart valve complications
  • Airway complications
  • Abnormalities in the flow of blood from the lungs to the heart
  • Bilaterally trilobed lungs – three lobes on each side of the lung (normally, the left lung has two lobes and the right lung has three lobes)
  • Missing spleen
  • Organs on the wrong side of the body

Polysplenia – this diagnosis may include:

  • Holes in the walls of the heart
  • Heart valve complications and problems with the heart's electrical system
  • Complete heart block, preventing electric communication between the upper and lower heart chambers
  • Airway complications
  • Missing spleen or multiple small spleens

Some conditions that may occur in the heart as a result of heterotaxy are:

  • Coarctation of the aorta
  • Tetralogy of Fallot
  • Transposition of the great vessels


Very little is known about the causes of heterotaxy and its different forms. Some forms may be genetic, either inherited or caused by a mutation in the genes as the baby begins to form in the early weeks of pregnancy. There are cases of more than one child in the family being diagnosed with heterotaxy. Both boys and girls develop the disorder. There are many forms of heterotaxy and in almost all cases they impact the functioning of the heart.

Who gets it?

Heterotaxy is diagnosed in both boys and girls of all racial and socio-economic backgrounds. In very rare cases, only boys of some families are affected.


Because the complications and heart defects caused by heterotaxy are so severe, most babies have symptoms as soon as they are born. Other babies may develop symptoms within a few days or weeks of being born. In those instances where heterotaxy has been diagnosed before birth, the symptoms occur after the child is born because while in the mother's womb, all the oxygen and nutrients needed are provided by the mother's blood. Depending on the severity, number of abnormalities and the organs affected, there are cases where polysplenia doesn't cause symptoms until later in childhood, or even into the adult years. Some of the symptoms your child may have are:

  • Purplish or bluish tint to the lips, nails and skin
  • Difficulty breathing, fast breathing
  • Unresponsiveness
  • Extreme sleepiness and fatigue
  • Difficulty feeding
  • Sweating during feeding
  • Heart murmur
  • Jaundice
  • Vomiting or abdominal swelling if intestines are blocked

Testing and diagnosis

Some cases of heterotaxy are diagnosed before the baby is ever born. If your obstetrician hears any abnormalities in your baby's heartbeat or sees any cause for concern in your baby's sonogram, you may be referred for a fetal echocardiography. This noninvasive ultrasound test is much like a sonogram but it provides much greater detail and can help to determine if your child will require special care immediately following their entry into the world. The Heart Center at Cook Children's one of only four centers in Texas to receive Intersocietal Commission for the Accreditation of Echocardiography accreditation, so you can trust that you and your baby are in very capable hands. Your testing will be performed by a pediatric cardiologist. If your child will require surgery or other critical care, you will meet with our pediatric medical team to determine the best care for you and your child.

Many times symptoms do not appear until after the baby is born. Testing to determine the cause and extent of the syndrome may include one, all or a combination of the following:

Because heterotaxy syndrome can be complex and involve multiple defects in the heart and many other organs, an entire team of pediatric specialists, which may include gastroenterologists, nephrologists, neurologists, pulmonologists and urologists, will be involved in the testing and diagnosis of your child's condition and work closely with your pediatric cardiologist to help determine the severity of the syndrome. As a very important part of our team, you will be included in making decisions about the care and treatment your child will receive.


Because heterotaxy can involve so many different disorders and defects in the heart and other organs, treating it can be a challenge. Many children will require more than one surgery. Because a child's body continually grows, often times multiple surgeries will occur, particularly before reaching full adulthood, but sometimes even into the adult years. Medications may be required to help regulate heart rhythm. Children without a spleen or whose spleen doesn't function properly will need to take antibiotics daily and receive certain vaccinations to help protect them from infections that their bodies are unable to fight off. Some children, teens or young adults may need to have a pacemaker or defibrillator implanted. Nearly all children with right atrial isomerism, and some with left atrial isomerism, will require a series of major heart surgeries. Some of the cardiac surgeries your child may undergo are:

  • Cardiac catheterization to place stents, devices and coils
  • Cardiac ablation to correct arrhythmias
  • Melody transcatheter pulmonary valve (Melody TPV)
  • Cardiothoracic surgery to correct complex defects in and relating to the heart, including blood flow and the treatment of complex heart lesions

Other surgeries may also include a liver transplant, intestinal corrective surgery, renal and pulmonary related surgeries.

Children with significant heart defects who receive corrective surgery have a much better outcome than those who do not. While this disorder is very complicated, the advancements in cardiovascular surgery in past few years can offer hope to families who are facing this disorder. Depending on how complex the diagnosis and the severity of the defects, many children do go on to enjoy a good quality of life all the way from childhood to adulthood.

Some heart disorders require ongoing care. Many of the heart patients here at Cook Children's have grown up with us and have become a part of our family as we take them through childhood and into adulthood. All children with heterotaxy require cardiac care throughout their lives. In many cases they will also need care from other medical teams. At Cook Children's your child will receive ongoing evaluations and care. Your family will also receive ongoing support so you are prepared to deal with the unique medical needs of your child. We also know that medical conditions can be very stressful emotionally, physically and financially. Our Child Life and Social Services teams are here to help you every step of the way, along with our many other support services, such as Home Health and on-staff nutritionists.

Appointments and referrals

Rare and complex congenital heart defects don’t always present a clear cut method of treatment. Often, there are multiple ways of approaching the diagnosis. Our physicians also are available to provide second opinions for families seeking alternative treatment options. If you would like to schedule an appointment, refer a patient or speak to our staff, please call our offices at 682-885-2140.