Transposition of the Great Arteries (TGA/TGV)

This is the CHD that the founder was born with.
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Transposition of the Great Arteries is one of the most common cyanotic CHDs. Sixty to 70 percent of the infants born with the defect are boys.

TGA occurs in 5 –7 % of all CHD…that is approximately 20 – 30 incidences per 100,000 live births

For no clear reason, the heart develops abnormally in the first 8 weeks of pregnancy. With TGA, the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle…the exact opposite of a normal heart’s anatomy. (see photo below).

Infants often appear cyanotic (blue) within days of life. The degree of cyanosis depends on the presence and degree of other defects (like an ASD that may allow for some mixing of the blood). Symptoms may include:

  • Rapid, labored breathing
  • Rapid heartbeat
  • Cool, clammy skin
  • Poor appetite

A diagnosis may be made from one or several of the following:

  • Chest x-ray – takes pictures on film and shows images of internal tissues and organs
  • Electrocardiogram EKG/ECG – tests electrical activity and shows abnormal rhythms
  • Echocardiogram – uses sound waves and evaluates structure and function of heart
  • Cardiac catherisation – an invasive procedure that takes blood pressures and oxygen measurements in the 4 chambers of the heart and the pulmonary artery and aorta. During cath, a contrast dye can be injected to clearly visualize structures inside the heart

Infants born with TGA can only survive if there is a shunt between the 2 sides of the heart.

Frequently, infants born with TGA may also have a VSD or ASD which allows for mixing of the blue and red blood (known as purple blood). This mixing is often not adequate enough to meet the body’s demands for oxygen. The child will most likely be administered prostaglandins (medicines that prevent the ductus arteriosus from closing therefore allowing mixing of blood). A “balloon atrial septostomy” may be performed to enlarge or stretch the foramen ovale (a connection between the left and right atrium that allows for mixing of blood) and thus creating a large ASD. Once safe oxygen levels and stable cardiac and pulmonary function is established, the child will need corrective surgery.

Further treatment will be based on the child’s age, overall health, medical history, extent of disease, tolerance to medications and procedures and the expectations for the course of the disease.

Doctors may proceed with one of the following surgeries:

Arterial Switch – This is the most commonly used method and is performed within the first month of life. During this procedure, the aorta is moved to the right ventricle and the pulmonary artery is moved to the left ventricle. The coronary arteries are also moved so that they will originate from the aorta and take oxygen rich blood to the heart. Other defects that may be present (ASD, VSD) will be closed.

Atrial Switch (Mustard or Senning operation) – A tunnel (also called a baffle) is made between the 2 upper chambers (atria) thus diverting oxygen rich blood to the right ventricle and aorta. The right ventricle will then pump blood to the entire body instead of just to the lungs as in a normal heart. This procedure was most commonly used during the 1960s – 1980s. However, this procedure has proven to have more long term complications such as arrythmias, baffle obstructions or leaks, heart valve leaks and decreased right ventricle function. Often, this procedure is used only when complications (such as narrowing of pulmonary valve) are present.

During the past 40 years, the survival rate for a newborn with TGA has improved remarkably from less than 10% within the first year of life to about 90% to the age of 20 years.

Consult you or your child’s physician regard the specific outlook for you or your child.

Disclaimer: The facts and opinions shown in this article are as accurate and up to date as possible, but are provided as general “information resources”, which may not be relevant to individual persons. This article is not a substitute for individual assessment and always take advice from a doctor who is familiar with the particular person.

Thanks to Vanessa at C.H.D. HEARTS – Hope for more tomorrows (CHD Heart Foundation)

Related Links

The British Heart Foundation are doing booklets for Parents of children to help understand their childs heart and the booklets are also for health professionals.

Here is the link for Transposition of the Great Arteries.
http://www.bhf.org.uk/publications/view_publication.aspx?ps=1000802