In congenitally corrected transposition of the great arteries, the normal connections of the aorta and the pulmonary artery are reversed, but the lower heart chambers (the ventricles) are also reversed, thus "correcting" the circulation so that the oxygen-poor venous blood goes into the lungs and oxygenated blood goes out to the body as it normally should. However, the circulation is not efficient because the right ventricle, which is designed to pump blood to the low pressure circulation through the lungs, is required to pump blood to the much higher pressure circulation to the body.
Infants with congenitally corrected transposition of the great arteries have many different symptoms because many additional heart abnormalities occur along with the switched heart chambers.
Long-term problems due to weakening of the heart muscle are likely to develop in adulthood due to the right ventricle supplying blood to the body.
The diagnosis is based on findings from a doctor's physical examination, electrocardiography (ECG), chest imaging, and cardiac catheterization.
Treatment is with medication to control symptoms, surgery to correct the defects, and pacemakers or implantable cardioverter-defibrillators if the abnormality causes an abnormal heart rhythm.
(See also Overview of Heart Defects.)
Congenitally corrected transposition of the great arteries is relatively rare. Most affected infants have other heart abnormalities as well, such as ventricular septal defect, pulmonic stenosis, and Ebstein anomaly.
Symptoms
These abnormalities result in a wide range of symptoms. An abnormally slow heart rhythm due to heart block may develop. In heart block, the electrical signals that control the heartbeat are partially or completely blocked between the upper and lower chambers of the heart. Heart block is treated with a pacemaker. In addition to the symptoms caused by any of the associated abnormalities, all people with congenitally corrected transposition are likely to develop symptoms secondary to having the circulation to the body supported by the right ventricle.
Infants may have a heart murmur due to pulmonic stenosis or a ventricular septal defect. If stenosis is severe and a ventricular septal defect is present, the skin and lips may appear bluish (cyanosis) because not enough oxygen is reaching the tissues. If a large ventricular septal defect is present, symptoms of heart failure, such as difficulty breathing and poor feeding, may occur. Symptoms may develop gradually during childhood and adolescence depending on the severity of the defects.
As children reach adulthood, the function of their right ventricle, which has taken on the work of the left ventricle, may begin to worsen, leading to an enlarged heart (cardiomyopathy) or heart failure. Often tricuspid regurgitation occurs, in which blood leaks backward through the tricuspid valve each time the right ventricle contracts.
Diagnosis
Stethoscope examination of the heart
Electrocardiography (ECG) and chest x-ray
Echocardiography (ultrasonography of the heart)
Magnetic resonance imaging (MRI) and computed tomography (CT)
Cardiac catheterization
Doctors are able to diagnose abnormalities of the heart by listening to the chest with a stethoscope. Doctors might hear a heart murmur or heart sounds might be louder on the right side if the chest than on the left. Subsequently, they usually perform an ECG and imaging studies.
Echocardiography (ultrasonography of the heart) and, sometimes, CT or MRI is used to show details of the anatomy and to evaluate the function of the ventricles.
Electrocardiography (ECG) may show heart block or other abnormalities, and chest x-rays show a change in the shape and position of the heart.
Treatment
Medication
Surgery
Pacemaker or implantable cardioverter defibrillator
Medication may be needed if heart failure develops.
Surgical treatment is often necessary for ventricular defects or tricuspid regurgitation.
Pacemakers or implantable cardioverter defibrillators may be needed if the congenital transposition causes abnormal heart rhythms.
If severe dysfunction develops, heart transplantation may be needed.
More Information
The following English-language resources may be useful. Please note that The Manual is not responsible for the content of these resources.
American Heart Association: Common Heart Defects: Provides overview of common congenital heart defects for parents and caregivers
American Heart Association: Infective Endocarditis: Provides an overview of infective endocarditis, including summarizing prophylactic antibiotic use, for patients and caregivers
