Levo-transposition of the great arteries pathophysiology


 * Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [mailto:psingh@perfuse.org]; ; Keri Shafer, M.D. [mailto:kshafer@bidmc.harvard.edu]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

Overview
In Levo-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.

General feature

 * 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.
 * 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.
 * The ventricles are inversely connected to the wrong great artery.

Physiology

 * 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.

Pathophysiology

 * 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.