Transposition of the Great Vessels, Corrected (L-TGA)

Michael P. D'Alessandro, M.D.
Peer Review Status: Internally Peer Reviewed

Etiology/Pathophysiology:
The ventricles and the great vessels are transposed. The morphologic right ventricle is on the left and the morphologic left ventricle is on the right, and there is L transposition of the great vessels. Systemic venous blood goes from the right atrium, across the mitral valve, into the left ventricle and then into the pulmonary artery. Oxygenated blood from the lungs returns to the left atrium, goes across the tricuspid valve into the right ventricle which connects with the aorta. This allows for no physiologic disturbance in pulmonary and systemic circulation, but there are frequently coexistent cardiovascular anomalies (VSD, left atrioventricular valve insufficiency, pulmonary artery outflow obstruction, ASD) which result in deranged cardiovascular circulation. Conduction anomalies are commonly present.

Pathology:
Not applicable

Imaging Findings:
The aorta arises anterior and superior to the origin of the pulmonary artery and forms the upper portion of the left cardiovascular border. The pulmonary trunk is not seen on the left. Cardiomegaly and increased pulmonary vascularity are present in patients with a VSD.

DDX:

• Transposition of the great arteries
• Double outlet right ventricle
• Taussig-Bing anomaly
• Truncus arteriosus
• Total anomalous pulmonary venous return
• Tricuspid atresia
• Single ventricle

References:
See References Chapter.

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