Transposition of the great arteries is a congenital (present at birth) heart defect. Due to abnormal development of the fetal heart during the first 8 weeks of pregnancy, the large vessels that take blood away from the heart to the lungs, or to the body, are improperly connected. Normally, oxygen-poor (blue) blood returns to the right atrium from the body, travels to the right ventricle, then is pumped through the pulmonary artery into the lungs where it receives oxygen. Oxygen-rich (red) blood returns to the left atrium from the lungs, passes into the left ventricle, and then is pumped through the aorta out to the body.
The obvious indication of TGA is a newborn who becomes cyanotic (blue) in the transitional first day of life when the maternal source of oxygen (from the placenta) is removed. Cyanosis is noted in the first hours of life in about half of the infants with TGA, and within the first days of life in 90 percent of them. The degree of cyanosis is related to the presence of other defects that allow blood to mix, including a patent ductus arteriosus - a fetal connection between the aorta and the pulmonary artery present in the newborn, which usually closes in the first few days after birth. The following are the other most common symptoms of TGA. However, each child may experience symptoms differently. Symptoms may include: rapid breathing labored breathing rapid heart rate cool, clammy skin The symptoms of TGA may resemble other medical conditions or heart problems. Always consult your child's physician for a diagnosis.
The heart is forming during the first 8 weeks of fetal development. The problem occurs in the middle of these weeks, allowing the aorta and pulmonary artery to be attached to the incorrect chamber. Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families. Most of the time this heart defect occurs sporadically (by chance), with no clear reason for its development.
A pediatric cardiologist and/or a neonatologist may be involved in your child's care. A pediatric cardiologist specializes in the diagnosis and medical management of congenital heart defects, as well as heart problems that may develop later in childhood. A neonatologist specializes in illnesses affecting newborns, both premature and full-term. Cyanosis is the major indication that there is a problem with your newborn. Your child's physician may have also heard a heart murmur during a physical examination. A heart murmur is simply a noise caused by the turbulence of blood flowing through the openings that allow the blood to mix. Other diagnostic tests are needed to help with the diagnosis, and may include the following: chest x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film. electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle stress. echocardiogram (echo) - a procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves. cardiac catheterization - a cardiac catheterization is an invasive procedure that gives very detailed information about the structures inside the heart. Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin, and guided to the inside of the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta. Contrast dye is also injected to more clearly visualize the structures inside the heart.
Specific treatment for transposition of the great arteries will be determined by your child's physician 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 Your child will most likely be admitted to the intensive care unit (ICU) or special care nursery once symptoms are noted. Initially, your child may be placed on oxygen, and possibly even on a ventilator, to assist his/her breathing. Intravenous (IV) medications may be given to help the heart and lungs function more efficiently. Other important aspects of initial treatment include the following: A cardiac catheterization procedure can be used as a diagnostic procedure, as well as initial treatment procedure for some heart defects. A cardiac catheterization procedure will usually be performed to evaluate the defect(s) and the amount of blood that is mixing. As part of the cardiac catheterization, a procedure called a balloon atrial septostomy may be performed to improve mixing of oxygen-rich (red) and oxygen-poor (blue) blood. A special catheter with a balloon in the tip is used to create an opening in the atrial septum (wall between the left and right atria). The catheter is guided through the foramen ovale (a small opening present in the atrial septum that closes shortly after birth) and into the left atrium. The balloon is inflated. The catheter is quickly pulled back through the hole, into the right atrium, enlarging the hole, allowing blood to mix between the atria. An intravenous medication called prostaglandin E1 is given to keep the ductus arteriosus from closing.