What is L-TGA Congenital Heart Defect?

Summary of L-TGA Heart Defect:

L-transposition of the great arteries is a form of congenital heart disease in which blood circulation flows in the way it should, but serious problems may still exist or develop and require treatment. Read on for information about the characteristics of the defect at birth and the treatment and follow-up care that is necessary into adulthood.

L-TGA in Childhood:

L-transposition of the great arteries (L-TGA) is also known as congenitally corrected transposition of the great arteries.This condition is different from D-transposition of the great arteries (d-TGA). In L-TGA, the right and left lower pumping chambers of the heart (ventricles) are switched. The deoxygenated “blue” blood from the right atrium goes to the left ventricle and is pumped to the lungs through the pulmonary artery, and “red” blood from the left atrium goes to the right ventricle and is pumped to the major artery to the body (the aorta). (Normally, the right ventricle pumps blood to the lungs.) In a baby with L-TGA, “blue” and “red” blood go where they are supposed to, so the arrangement of the heart is “corrected,” even though the pumping chambers are switched.

What are some symptoms of L-TGA?

L-TGA is commonly associated with other heart problems, such as a hole in the wall between the ventricles (ventricular septal defect, or VSD) and an abnormal tricuspid valve connected to the right ventricle (Ebstein’s anomaly). These other problems contribute to the development of heart failure in children and adults with this defect. This defect can also cause problems with irregular heart rhythms, most commonly, complete heart block, which may require a pacemaker. However, if there are no other associated heart problems (VSD or Ebstein’s anomaly), some children can go undiagnosed for many years, even to adulthood.

What are the complications with L-TGA?

In rare instances where there are no other associated heart defects, patients can live to adulthood without surgery. However, the right and left ventricles are functionally differently so that the usual right ventricle is not equipped to consistently pump against the higher pressure in the arteries of the body. Children with other heart problems may require surgery early in life to help the heart function better. These patients can develop heart failure without surgery.

What are the treatments for L-TGA?

Several options exist if surgery is needed. The VSD can be closed with a patch, but this leaves the “wrong” ventricles connected to their respective great arteries. Ebstein’s anomaly can sometimes be repaired, but may require valve replacement.

Some patients undergo a surgery called a “double switch.” This is two operations performed at the same time. The first part of the operation is an atrial switch. There are two names for this surgery depending on how the surgeon performs it, either a Mustard or a Senning operation. The operation reroutes blood from the right atrium to flow to the right ventricle and blood from the left atrium to flow to the left ventricle.

The second part of this operation is an arterial switch. This involves disconnecting the pulmonary artery and the aorta, switching them and sewing them back to their proper ventricle. In this manner, blood from the right ventricle goes to the pulmonary artery and blood from the left ventricle goes to the aorta. Additionally, the coronary arteries must be reconnected to the vessel that becomes the aorta.