Transposition of the Great Arteries:

Transposition of the great arteries is a rare congenital heart defect in which the two main arteries, the aorta and the pulmonary artery that carry out blood away from the heart are swapped (transposed). In cases of transposition of the great arteries, these vessels arise from the wrong ventricle. Therefor the aorta carries deoxygenated blood from the right ventricle and the pulmonary artery carries out oxygenated blood from the left ventricle. This results in shortage of oxygen in blood flowing from the heart to the rest of the body. Transposition of the great arteries is usually detected within the first hours to weeks of life. Without a sufficient supply of oxygen rich blood, the body cannot function properly and it can lead to serious complications or death without treatment.

Signs and Symptoms:

Symptoms appear at birth or very soon afterwards. How bad the symptoms are depends on whether there is a way for the two separate blood circuits to mix, allowing some oxygen-rich blood to get out to the body. This mixing can occur through other defects, such as a hole between the bottom chambers of the heart (a ventricular septal defect), or through a shunt that normally is present at birth. Symptoms also can depend on whether other defects are present as well. Common symptoms of TGA include:

• Blueness of the skin
• Shortness of breath
• Poor feeding

Surgery might be needed shortly after birth. Without corrective surgery, severe cases of TGA can be fatal during the first 6 months of life. Babies who have surgery to correct TGA sometimes have the following associated conditions later in life:

• Leaky heart valves
• Problems with the arteries that supply the heart muscle with blood (coronary arteries)
• Abnormal heart rhythm (arrhythmias)
• A decline in function of the heart muscle or heart valves
• Heart failure
• Damage to the lungs and difficulty breathing

Diagnosis:

A physical exam alone isn’t enough to accurately diagnose transposition of the great arteries, however. One or more of the following tests are necessary for an accurate diagnosis:

• Echocardiography. An echocardiogram is an ultrasound of the heart. Doctors use this test to diagnose transposition of the great arteries by looking at the position of the aorta and the pulmonary artery. Echocardiograms can also identify associated heart defects, such as a ventricular septal defect, atrial septal defect, or patent ductus arteriosus.
• Chest X-ray. Although a chest X-ray doesn’t provide a definitive diagnosis of transposition of the great arteries, it does allow the doctor to see your baby’s heart size and the position of the aorta and pulmonary artery.
• Electrocardiogram. An electrocardiogram records the electrical activity in the heart each time it contracts. During this procedure, patches with wires (electrodes) are placed on your baby’s chest, wrists and ankles. The electrodes measure electrical activity, which is recorded on paper.
• Cardiac catheterization. This procedure is typically done only when other tests, such as echocardiography, don’t show enough information to make a diagnosis. Cardiac catheterization may also be done urgently to perform a temporary treatment for transposition of the great arteries (balloon atrial septostomy).

Treatment:

All infants with transposition of the great arteries need surgery to correct the defect.

Before surgery:

The doctor may recommend several options to help manage the condition before corrective surgery. They include:

• Medication. The medication prostaglandin E1 (alprostadil) helps keep the connection between the aorta and pulmonary artery open (ductus arteriosus), increasing blood flow and improving mixing of oxygen-poor and oxygen-rich blood until surgery can be performed.
• Atrial septostomy. This procedure — usually done using cardiac catheterization rather than surgery — enlarges a natural connection between the heart’s upper chambers (atria). It allows for the oxygen-rich and oxygen-poor blood to mix and results in improved oxygen delivery to your baby’s body.
  Surgery

Surgical options include:

• Arterial switch operation. This is the surgery that surgeons most often use to fix transposition of the great arteries. Doctors usually perform this surgery within the first month of life.

During an arterial switch operation, the pulmonary artery and the aorta are moved to their normal positions: The pulmonary artery is connected to the right ventricle, and the aorta is connected to the left ventricle. The coronary arteries also are reattached to the aorta.

If your baby has a ventricular septal defect or an atrial septal defect, those holes usually are closed during surgery. In some cases, however, the doctor may leave small ventricular septal defects to close on their own.

• Atrial switch operation. In this surgery, the surgeon makes a tunnel (baffle) between the heart’s two upper chambers (atria). This diverts the oxygen-poor blood to the left ventricle and the pulmonary artery and the oxygen-rich blood to the right ventricle and the aorta. With this procedure, the right ventricle must pump blood to the entire body, instead of just to the lungs as it would do in a normal heart. Possible complications of the atrial switch operation include irregular heartbeats, baffle obstructions or leaks, and heart failure due to problems with right ventricle function.

–https://www.youtube.com/watch?v=lBGUtiBp8k8
–http://www.mayoclinic.org/diseases-conditions/transposition-of-the-great-arteries/basics/definition/con-20043232
–http://en.wikipedia.org/wiki/Transposition_of_the_great_vessels
–http://www.cdc.gov/ncbddd/heartdefects/TGA.html
–http://www.mayoclinic.org/diseases-conditions/transposition-of-the-great-arteries/basics/tests-diagnosis/con-20043232
–http://www.mayoclinic.org/diseases-conditions/transposition-of-the-great-arteries/basics/treatment/con-20043232
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