Heterotaxy Syndrome (Isomerism)

Some babies are born with an abnormal placement of organs in the body, like a puzzle whose pieces got a little jumbled up. The heart might be located in the right side of the chest instead of the left, and other organs, such as the lungs, stomach, liver and spleen, might also develop abnormally and be out of place. The word “heterotaxy” means “different arrangement.” Heterotaxy syndrome is a very rare condition, affecting about 1 in 10,000 babies and approximately 3% of people with congenital heart defects.

About heterotaxy syndrome

There’s no textbook case of heterotaxy because this condition affects every patient differently. However, heart defects are one of the most common features and can vary in type and severity. A baby’s intestines might also be twisted (malrotation), the spleen might be missing entirely or divided into multiple pieces, and there might be issues with the skeleton, central nervous system and urinary tract.

Another term for heterotaxy is isomerism. Some organs of the body are left sided or right sided. The liver usually lives on the right side; the spleen on the left. Children with heterotaxy have two left sides or two right sides, causing organs to be abnormal. There are no two patients alike, but two main types of heterotaxy syndrome include:

• Right atrial isomerism - The heart has two right atria and usually multiple heart defects, such as valve problems, septal defects (holes in the heart’s dividing walls), and possibly transposition of the great arteries and/or single ventricle defect (when there’s only one effective pumping chamber).
• Left atrial isomerism - The heart has two left atria and possible valve defects, septal defects and problems with the heart’s electrical system. 

Experts in treating heterotaxy syndrome

Heterotaxy syndrome is often associated with complex heart defects that should be treated at a center that specializes in congenital heart disease. The Herma Heart Institute is one of the nation’s top pediatric heart programs and consistently delivers some of the best congenital heart surgery outcomes for even the most complex types of heart disease. Families from across the nation have traveled to Wisconsin for our expertise in treating heterotaxy. If your child has already been diagnosed at another center, we invite you to get a second opinion for heterotaxy at the Herma Heart Institute.

The Herma Heart Institute is also home to our Fetal Heart Program and Adult Congenital Heart Disease Program, allowing for seamless, high quality care for heterotaxy syndrome across your child’s lifespan.

What causes heterotaxy syndrome?

During the early stages of pregnancy, something throws off the body’s usual left-right orientation and organs don’t form in the typical locations or in the usual ways. A child might inherit certain gene mutations associated with heterotaxy, a gene mutation could occur spontaneously, or it could be triggered by the mother’s exposure to a chemical or toxin during pregnancy. Sometimes there is no known cause.

Why is heterotaxy syndrome a concern?

This condition affects not just the placement of organs in the body, but also how those organs function. Children with this condition might have difficulty breathing, digesting food and resisting infection. If untreated, some complications of heterotaxy syndrome can become life-threatening.

What are the symptoms of heterotaxy syndrome?

In cases where the heart problems are severe, a baby with this condition might show the following symptoms soon after birth:

• Bluish lips, skin and nails
• Lethargy
• Rapid breathing
• Poor feeding

In some cases, a child might not show any symptoms. Always consult your child’s doctor if you have concerns or notice anything new.

How is heterotaxy syndrome diagnosed?

• Chest x-ray - Uses electromagnetic energy beams to produce images of internal tissues, bones and organs onto film
• Electrocardiogram (ECG or EKG) - Records the electrical activity of the heart, shows abnormal rhythms and detects heart muscle stress
• Echocardiogram (echo) - Evaluates the heart’s structure and function by using sound waves recorded on an electronic sensor to produce a moving picture of the heart and heart valves 
• Cardiac catheterization - A small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin and guided to the heart to get very detailed information about the structures inside the heart
• Cardiac MRI - Uses a magnet, radio waves and a computer to create very detailed, 3D still and moving images of major blood vessels and the heart as it beats

In less severe cases, heterotaxy syndrome might go undetected for years.

Treatment for heterotaxy syndrome

Children’s heterotaxy specialists will recommend the best treatment for your child based on:

• Your child’s age, overall health and medical history
• Extent of the disease
• Your child’s tolerance for specific medications, procedures or therapies
• Expectations for the course of the disease
• Your opinion or preference

Treatment could include:

Medical management – Some children with heterotaxy syndrome might need medications, including:

• Digoxin - To strengthen the heart muscle, enabling it to pump more efficiently
• Diuretics - To help the kidneys remove excess fluid from the body, which is sometimes needed when the heart isn’t working as well as it could
• Antibiotics - To prevent a heart infection called bacterial endocarditis after routine dental work or other procedures, which can be a risk for children with certain heart defects.

Surgical repair – Most patients with heterotaxy syndrome require multiple surgical procedures, but treatment depends on the specifics of your child’s case. Heart procedures could include repairing holes or implanting a pacemaker to control the heart’s rhythm. More severe cases might require major heart surgeries to reconstruct the heart so that it can function with a single pumping chamber (a three-stage process involving the Norwood, Glenn and Fontan procedures). The Herma Heart Institute is internationally renowned for its expertise in these procedures.

A surgical repair is performed while your child is under general anesthesia, and some defects can be corrected during a cardiac catheterization procedure while your child is sedated. Your cardiologist will advise you on the best options for your child.

Postoperative care for your child

After surgery, your child will spend time in the cardiac intensive care unit (CICU) for several hours or overnight. During the first several hours after the procedure, your child will likely be drowsy from the anesthesia and medications given to ease anxiety and pain. Over time, your child will become more alert.
While your child is in the CICU, Children’s might use the following equipment:

• Ventilator - This machine helps your child breathe. A small, plastic tube is guided into the windpipe and attached to the ventilator, which breathes for your child while they are under anesthesia. Many children have the ventilator tube removed right after surgery, but some will benefit from remaining on the ventilator for a few hours or days afterward so they can rest.
• Intravenous (IV) catheters - These small, plastic tubes inserted into blood vessels provide IV fluids and important medications that help your child recover from the operation.
• Arterial line - A specialized IV placed in the wrist, or other area of the body where a pulse can be felt, measures blood pressure continuously during surgery and while your child is in the ICU.
• Nasogastric (NG) tube - A small, flexible tube keeps the stomach drained of acid and gas bubbles that could build up during surgery.
• Urinary catheter - This small, flexible tube drains urine out of the bladder and accurately measures how much urine the body makes, which helps determine how well the heart is functioning. Some swelling and puffiness is common after surgery, and your child might be given diuretics to help the kidneys remove excess fluids.
• Chest tube - A drainage tube might be inserted to keep the chest free of blood that would otherwise accumulate after the incision is closed. Bleeding can occur for several hours or even a few days after surgery.
• Heart monitor - This machine constantly displays a picture of your child’s heart rhythm and monitors heart rate, arterial blood pressure and other values.

Your child might need other supportive equipment while in the CICU or afterward. They will be kept as comfortable as possible with medications that relieve pain and anxiety, and the staff might also ask for your input on how best to soothe and comfort your child.

After your child is discharged from the CICU, they will recuperate on another hospital unit for a few days before going home. You will learn how to care for your child at home and will receive instructions on medications, activity limitations and follow-up appointments before your child is sent home.

Care for your child at home following heterotaxy surgical repair

Most children feel fairly comfortable when they go home, and your physician might recommend pain medications, such as acetaminophen or ibuprofen, to keep them comfortable. Your child might become tired more quickly than before surgery, but they usually will be allowed to play with supervision. It’s important to avoid blows to the chest that might cause injury to the incision or breastbone. Within a few weeks, your child should be fully recovered and able to participate in normal activity.

Long-term outlook after heterotaxy surgical repair

The outlook for heterotaxy syndrome depends on the severity of your child’s condition. After the necessary surgical repairs, many children do well. Others might require repeat surgeries or develop complications that require ongoing care. Your child will always need to be monitored by a cardiologist in case new problems develop, and once they reach adulthood, they should seek out a program that specializes in adult congenital heart disease like Children’s ACHD program.