Transposition of the Great Arteries

(D-) Transposition of the Great Vessels: This occurs when the great vessels (aorta and pulmonary artery) are reversed. Some cardiologists say that the circulation is “in parallel” rather than “in series”. This means that the blue blood, which is pumped through the right side of the heart, bypasses the lungs, going directly out the aorta. The red blood comes directly from the lungs into the left side of the heart, where it gets pumped back to the lungs.

This defect is not compatible with life, unless there is a hole somewhere within the heart (see “ASD”), or if the ductus stays open (see “PDA”). These “defects” allow the two circulations to “mix” until the heart defect can be definitively fixed by surgery.

Aorta (AO)
Pulmonary Artery (PA)
Right Atrium (RA)
Left Atrium (LA)
Right Ventricle (RV)
Left Ventricle (LV)