Pediatric Transposition of the Great Arteries (TGA)

Transposition of the great arteries (TGA) is a type of heart defect that your baby is born with (congenital). In this condition, the two arteries that carry blood from the heart to the lungs and body aren’t connected as they should be. They are reversed (transposed).

In TGA, the following occurs:

• The aorta is connected to the right ventricle. It should normally be connected to the left ventricle.
• The pulmonary artery is connected to the left ventricle when it should normally be connected to the right ventricle.

This means that:

• Oxygen-poor (blue) blood is sent to the body instead of to the lungs.
• Oxygen-rich (red) blood returns to the lungs instead of going to the body.

This is the opposite of a normal heart.

Babies can't live with this condition unless they get treatment.

TGA may occur on its own. Or your child may also have other heart problems in addition to TGA. These might include blockage of blood flow from the right ventricle to the aorta, or variations in the course of the coronary arteries. Other heart problems such as holes in the walls between the upper and lower chambers of the heart (atrial or ventricular septal defects) may allow some oxygen-rich blood to be sent to your baby’s body. Also, some parts your baby's heart may stay intact to allow oxygen-rich blood to reach your child's body. Normally, these connections would close shortly after birth.

Common heart defects that can happen with TGA include an opening in the ventricular septum, called a ventricular septal defect (VSD). This is a hole between the two lower chambers of the heart. This allows oxygen-poor and oxygen-rich blood to mix.

Most of the time, the cause of TGA isn’t known.

Most babies with TGA have blue skin color (cyanosis) in the first hours or days of their lives.

Other symptoms that can occur include:

• Fast breathing
• Trouble breathing
• Fast heart rate
• Poor feeding

The symptoms of TGA may be similar to symptoms of other conditions. Make sure that your child sees his or her healthcare provider for a diagnosis.

If your child has signs of TGA after birth, a pediatric cardiologist or neonatologist will check him or her. A pediatric cardiologist is a doctor with special training in treating heart problems in babies and children. A neonatologist is a doctor with special training in treating problems in newborns. These doctors will be part of your baby’s heart care team.

Your child’s doctor may do tests to confirm the diagnosis. The tests your child has depends on his or her age and condition, and the doctor’s preferences.

Pulse oximetry

For this test, a probe is placed on your child's finger or toe. It measures the level of oxygen in the blood, if it is below a certain level, this may be a sign of TGA.

Chest X-ray

A chest X-ray shows the size and shape of the heart and lungs.

Electrocardiogram (ECG)

This test records the electrical activity of the heart. It also shows abnormal rhythms (arrhythmias or dysrhythmias) and spots heart muscle stress.

Echocardiogram (echo)

An echo uses sound waves to make a moving picture of the heart and heart valves. This test may show TGA.

Cardiac catheterization (cardiac or heart cath)

A cardiac catheterization gives detailed information about the structures inside the heart. In this test, a small, thin, flexible tube called a catheter is put into a blood vessel in your child’s groin. Then the healthcare provider guides it to your child’s heart. Your child’s healthcare provider will inject your child with contrast dye to see his or her heart more clearly. This test measures your child’s blood pressure and oxygen in the 4 chambers of the heart and the pulmonary artery and aorta. Your child will get medicine to help relax and prevent pain (sedation).

All children with a TGA will need to have surgery to fix it. Your baby will likely be admitted to the intensive care unit (ICU).

Medical management

At first, your baby may get the following care:

• Supplemental oxygen or a ventilator. This is a machine that helps do the work of breathing for the baby.
• Different types pf medicine given by IV. This will help your baby’s heart and lungs work better.
• A medicine called prostaglandin E1. This is used to keep the ductus arteriosus open. This allows blood to flow through the heart until surgery can be done.

Cardiac catheterization

Your child may have a test called a balloon atrial septostomy. This is done during cardiac catheterization. This test makes it easier for oxygen-rich blood to reach the rest of the body by creating or enlarging an atrial septal defect which allows oxygen-rich blood and oxygen-poor blood to mix.

Surgery

Typically, in the first few weeks of life, your baby will need surgery for TGA. This procedure is called an arterial switch. Your child’s surgeon will connect the aorta and pulmonary artery to their normal ventricles. The surgeon will also have to move the coronary arteries. The surgeon will also fix any other heart problems, such as a VSD.

Complications of untreated TGA include:

• Heart valve problems
• Heart muscle problems or problems with the arteries that supply blood to the heart muscle
• Abnormal heart rhythm
• Heart failure
• Lung problems
• Death

Your child will stay in the hospital until surgery. Your child’s healthcare team will tell you how to care for your baby before you leave the hospital. He or she may also give you information about home healthcare for your baby, if you need it.

Most children who have surgery for this condition will grow and develop normally. Ask your child's healthcare provider about your child’s outlook. Your child will still need to see his or her heart doctor for checkups. Your child may need additional surgeries or cardiac catheterizations in the future.

Your child's doctor may give him or her antibiotics before surgeries or dental procedures. This is to prevent infections. Your child may also need to limit physical activity and avoid certain sports. Ask your child’s heart doctor what activities are safe for your child.

If your child has trouble breathing or any new symptoms, call his or her healthcare provider.