Levo-Transposition of the Great Arteries (L-TGA) occurs when the connections between the atria and ventricles, and the ventricles and arteries are abnormal. Because the ventricles are not in the correct position, the right ventricle has to do the work that the left ventricle is supposed to do — pumping blood to the body. The right ventricle gets overworked and becomes weak.

Many patients with L-TGA will have additional heart abnormalities. This includes holes in the heart, such ventricular septal defects (VSDs) and atrial septal defects (ASDs), as well as valve abnormalities. These other abnormalities can affect the blood flow patterns.

Patients with L-TGA can have a variety of symptoms, including:

  • Difficulty breathing
  • Difficulty exercising
  • Tiring more easily

Symptoms can range from mild to more severe.

Patients with L-TGA have a higher risk of heart rhythm problems. They may also develop heart block, which happens when the heart's electrical activity does not travel normally from the atria to the ventricles.

L-TGA – Causes and Diagnosis

L-TGA can be present in infants, children and adults. In most cases, there is no known cause for L-TGA and there are no specific genetic syndromes seen with L-TGA.

This heart condition is usually diagnosed with an echocardiogram — an ultrasound of the heart — or by a fetal echocardiogram before birth.

Care Providers

The University of Maryland Children's Heart Program team that treats L-TGA includes a pediatric cardiac surgeon, pediatric cardiologists, pediatric and neonatal intensive care doctors and nurses, pediatric cardiac anesthesiologists, cardiac operating room staff, cardiac nurses and many others with expertise in providing this specialized cardiac care. 

Treating L-TGA

Patients who have only L-TGA with no other major heart problems, no symptoms and normal function of the right ventricle may not require heart surgery. They will need to be closely monitored for any changes.

In more serious L-TGA cases, patients may have surgery to close holes in the heart (ASDs or VSDs) or to repair valves. A more complicated surgery, called a double switch operation, may be needed to relieve the right ventricle and make the left ventricle the pump to the body. This surgery involves rerouting the blood return from the body and lungs, and also switching the route of the arteries so that the blood flows to the correct places.

The timing of the double switch operation is important. If the left ventricle does not pump at high pressures for a long time, its muscle will get weaker. In young patients, the muscle may need to be retrained to make it strong enough to pump blood through the body. This retraining may require surgeries before the double switch to make the left ventricle stronger.

If the left ventricle goes too long without pumping at high pressure, it may not be able to be retrained and the double switch may not be possible. Continual monitoring of L-TGA is required.

Patients with L-TGA may require repeat procedures or surgeries, and some who have poor function of the right ventricle may eventually need a heart transplant.

All patients will need lifelong follow up with a cardiologist.

Contact Us

  • To learn more about Maternal Fetal Heart medicine, please call 410-328-3865.
  • To make an appointment with a Children's Heart Program physician, please call 410-328-4348.