Above. Post-delivery anatomy. In L-TGA or CC-TGA, the ventricles are transposed with the right ventricle on the baby’s left side and the left ventricle is on the baby’s right side. The right and left atria remain in their normal anatomic location with the left atrium connecting to the transposed right ventricle and the right atrium connecting to the transposed left ventricle. The aorta arises from the transposed ventricle on the left (the morphologic right ventricle) and the pulmonary artery arises from the transposed ventricle on the right (the morphologic left ventricle). The great arteries (aorta and pulmonary) are in parallel orientation. The circulation itself remains normal except the pumping chambers are different with the right ventricle pumping blood to the body through the aorta and the left ventricle pumping blood to the lungs via the pulmonary artery. As the right ventricle supports the systemic circulation instead of the left ventricle, the right ventricle’s greater work burden may result in strain and heart failure.
Other associated defects include: VSD, valve abnormalities, tricuspid valve regurgitation, Ebstein anomaly, left ventricular outflow tract obstruction, pulmonary and sub-pulmonary stenosis, dextrocardia, and rhythm abnormalities including complete heart block.