Congenital Transposition of Great Arteries

November 12, 2012

Congenital Transposition of Great Arteries

This can be a worrying condition for new parents to deal with, especially as it usually occurs with other heart problems and can affect the life expectancy of the new child.

In the early stages of pregnancy there may be some abnormal development of the fetal heart leading to a congenital heart defect known as transposition of the great arteries this is the second most common congenital heart defect seen in babies and appears to occur most often in boys. Great arteries are the primary arteries of the heart – the pulmonary artery and the aorta; congenital means the condition is present at birth, transposition – as the name implies – means that these great arteries, which take blood from the heart to the lungs, are not corrected properly.

Normal heart function

When the heart is functioning as it should be de-oxygenated, or blue, blood returns to the right atrium of the heart, crosses to the right ventricle and is then pumped, via the pulmonary artery, into the lungs where it becomes oxygenated, or red, blood before travelling back to the heart via the left atrium, into the left ventricle and finally back into the body via the aorta.

When transposition occurs

When transposition occurs in the great arteries the connections are the opposite of those seen in a normally functioning heart. When this happens two separate circuits will be formed within the heart.

  • De-oxygenated blood is circulated straight back to the body as the blue blood passes from the right ventricle into the misconnected aorta.

  • Oxygenated blood is circulated straight back to the lungs as the red blood passes through the left atrium, into the left ventricle through the pulmonary artery back to the lungs.

Babies with transposition of the great arteries are often found to have other associative heart defects – which often contribute to the survival of the infant.

So called ‘purple blood’ may be created via an opening in the atria or ventricular septum which allows blood from one side to mix with the other.

Patent ductus arteriosus also allows for the development of purple blood as the blue and red bloods are mixed through the aorta and pulmonary connection.

The development of this purple blood is beneficial in that it allows some oxygen into the body, the reduced levels of oxygen often results in babies with transposition of the great arteries to be labeled as ‘blue babies’.

Why does it happen?

In most cases there is no known cause for the development of the transposition of the great arteries and it appears to be a condition which occurs solely by chance.

What are the symptoms?

The most obvious symptom is, of course, a blue tinge to the baby’s skin tone. Although there are some general symptoms different children will often present differently -

  • Rapid and/or labored breathing

  • Rapid heart beat

  • Cool, clammy skin

Because symptoms of transposition of the great arteries can also mimic other medical conditions if you are c0ncerned about the health of your baby you should always seek the advice of your medical practitioner.

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