Congenitally Corrected Transposition of the Great Arteries
What is congenitally corrected transposition of the great arteries?
Congenitally corrected transposition of the great arteries (CCTGA) is a rare heart defect. Only 0.5 to 1 percent of all people with heart defects have CCTGA. This means there are about 5,000 to 10,000 people in the United States with this condition.
In CCTGA both ventricles (pumping chambers) of the heart are reversed. Fortunately, the arteries are reversed too, so the heart actually "corrects" the abnormal development, thus the name "congenitally corrected transposition of the great arteries." However, CCTGA is a complex malformation in which the heart is far from being normal.
In a normal heart, the left-side pumping chamber (left ventricle) sends blood to the entire body. The right-side ventricle pumps blood only a short distance, to the lungs. The left ventricle is built to last longer than the right ventricle: 80 to 100 years if no other health problems exist.
In congenitally corrected transposition of the great arteries (CCTGA), the heart twists abnormally during fetal development, and the ventricles are reversed: The stronger left ventricle pumps blood to the lungs and the weaker right ventricle has the harder chore of pumping blood to the entire body. The right ventricle is not built to last as long as the left ventricle.
CCTGA can cause problems, particularly for the right ventricle, which must work harder than it was meant to. After many years, the ability of the right ventricle to continue to function effectively will determine how well a person with CCTGA is.
There are several problems that also occur in many patients with CCTGA. The most common problems are:
- A ventricular septal defect (VSD): a hole between the two pumping chambers of the heart.
- A blockage of the blood on the way to the lungs (pulmonary stenosis).
- An abnormal valve that tends to leak (Doctors call this an “Ebstein-like” tricuspid valve.)
- A blockage in the electrical conduction system: Hearts use an electrical impulse to make their muscles contract. In CCTGA the electrical conduction system can get “blocked” and patients may require a pacemaker.
Signs and symptoms of CCTGA
People with CCTGA experience a wide variety of symptoms, depending on other problems with the heart. There are sick newborns, with low oxygen level, who need care immediately after birth, and there are healthy people who can live a normal life for many years, without any treatment.
In one case, a woman was diagnosed with CCTGA at age 83, after having five children. On the other hand, some babies born with CCTGA die in infancy. Many people with CCTGA have no or few symptoms as children and young adults, but develop problems as they age. CCTGA is often not diagnosed until adolescence or adulthood, when problems develop because of the leaky heart valve, abnormal electrical conduction in the heart, or inability of the right ventricle to continue the hard work of pumping blood to the entire body.
Symptoms may include fainting from the block in the electrical conduction, or fatigue, as the heart is unable to pump enough blood to the body.
Testing and diagnosis of CCTGA
Diagnosis of CCTGA may require some or all of these tests.
- Echocardiogram (also called “echo” or ultrasound): sound waves create an image of the heart
- Chest X-ray
- Electrocardiogram (ECG): a record of the electrical activity of the heart
- Cardiac MRI: a three-dimensional image that shows the heart’s abnormalities
- Cardiac catheterization: a thin tube is inserted into the heart through a vein and/or artery in either the leg or through the umbilicus (“belly button”)
Echocardiogram and cardiac MRI are most commonly used in the diagnosis of CCTGA.
Treatment for CCTGA
Treatment for CCTGA varies according to the type and severity of symptoms and associated defects. In some patients, especially those that have no additional heart defects, there may not be a need to do anything.
For patients that do need surgery, the type of operation will vary according to the associated defects. There are several operations used in this condition, including:
- Closure of the hole in the heart (VSD) and insertion of a tube (conduit) between the heart and the lungs. The conduit may need to be exchanged at a later date, requiring another operation.
- Leaving the VSD open and repairing the heart as if it had only one pumping chamber (ventricle). This is called a Fontan repair and involves connecting the veins that bring blood without oxygen back to the heart to go directly to the lungs to pick up oxygen, bypassing the heart.
- Double switch operation. Surgeons redirect blood flow from one side of the heart to the other. The heart's major arteries are also switched during this operation. This corrects the circulation so that the heart's left side serves the body and the right side serves the lungs. This is a very complex operation and is usually performed in infants and children. The double switch procedure is very rarely used in adults.
Any of the above operations may also have to include replacement of the leaky tricuspid valve with an artificial valve, and insertion of a pacemaker.
Because those operations are complex and difficult, they are best performed in centers with large patient volume, resources and experience, like the Cardiac Center at Children's Hospital.
Outlook for CCTGA
Because of enormous strides in medicine and technology, today many children born with congenitally corrected transposition of the great arteries go on to lead healthy, productive lives as adults. Outcomes are also better for those born without additional heart defects.
Congenitally corrected transposition of the great arteries is a complex heart condition. Some related complications begin and can be treated early in childhood, but others develop later in life. CCTGA requires life-long care by a cardiologist experienced in congenital heart disease.
Our pediatric cardiologists follow patients until they are young adults. Then care is taken over by a special service we have for adults with congenital heart disease (ACHD), called the Philadelphia Adult Congenital Heart Center. The American College of Cardiology has recommended that CCTGA patients be seen regularly at regional ACHD centers. The Philadelphia Adult Congenital Heart Center, a joint program of The Children's Hospital of Philadelphia and Penn Medicine, meets the unique needs of adults who were born with heart defects.
We will help patients transition their care to our Philadelphia Adult Congenital Heart Center, or to a cardiologist with congenital heart disease expertise in another location.
Reviewed by Paul Stephens, MD