Levo-transposition of the great arteries pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editors-In-Chief: Keri Shafer, M.D. [2]; Atif Mohammad, M.D., Priyamvada Singh, MBBS

Pathophysiology

Levo-transposition of the great arteries is a defect in which atrial and ventricular morphologies are discordant, and also the morphology of each ventricle is discordant with the great artery that comes from it. In other words this anomaly is a "double discordance" with both atrioventricular and ventriculoarterial discordance, which essentially "corrects" the physiologic abnormality. The atria are in normal position and received appropriate venous return, but the atria are connected to the opposite ventricle (RA to the LV and LA to the RV). In addition the ventricles are inversely connected to the wrong great artery.

In a normal heart, oxygen-depleted ("blue") blood is pumped from the right atrium into the right ventricle, then through the pulmonary artery to the lungs where it is oxygenated. The oxygen-rich ("red") blood then returns, via the pulmonary veins, to the left atrium from which it is pumped into the left ventricle, then through the aorta to the rest of the body, including the heart muscle itself.

With l-TGA, blue blood is pumped from the right atrium into the morphological left ventricle (which lies on the right side of the heart), then through the pulmonary artery to the lungs. The red blood then returns, via the pulmonary veins, to the left atrium from which it is pumped into the morphological right ventricle, then ejected into the aorta.

Acknowledgements and Initial Contributors to Page

Leida Perez, M.D.

External links

• Diagram at kumc.edu
• Diagram and description at umich.edu
• Overview at pediheart.org
• Royal Children's Hospital, Melbourne
• Mayo Clinic, Arizona - Florida - Minnesota, USA