<unk>  (d-Transposition of the great arteries, dextro-TGA, or<unk> , sometimes also referred to as complete<unk>  of the great arteries, is a birth defect in the large arteries of the heart. The primary arteries (the aorta and the pulmonary artery) are transposed.
It is called a cyanotic congenital heart defect (CHD) because the newborn infant turns blue from lack of oxygen.
In segmental analysis, this condition is described as ventriculoarterial discordance with atrioventricular concordance, or just ventriculoarterial discordance.<unk>  is often referred to simply as<unk>  of the great arteries (TGA); however, TGA is a more general term which may also refer to levo-transposition of the great arteries (l-TGA).
Another term commonly used to refer to both<unk>  and l-TGA is<unk>  of the great vessels (TGV), although this term might have an even broader meaning than TGA.
In a normal heart, oxygen-depleted ("blue") blood is pumped from the right side of the heart, through the pulmonary artery, to the lungs where it is oxygenated. The oxygen-rich ("red") blood then returns to the left heart, via the pulmonary veins, and is pumped through the aorta to the rest of the body, including the heart muscle itself.
With<unk> , blue blood from the right heart is pumped immediately through the aorta and circulated to the body and the heart itself, bypassing the lungs altogether, while the left heart pumps red blood continuously back into the lungs through the pulmonary artery. In effect, two separate "circular" (parallel) circulatory systems are created, rather than the "figure 8" (in series) circulation of a normal cardio-pulmonary system.
Differences in the shape of the atrial septum and/or ventricular outflow tracts affect the relative positions of the aorta and pulmonary artery. In the majority of<unk>  cases, the aorta is anterior and to the right of the pulmonary artery, but it can also be directly anterior or anterior and to the left. The aorta and pulmonary artery can also be side by side, with aorta on either side. This is a less common variant, and with this arrangement, an unusual coronary artery pattern is common. There are also some cases with aorta to the right and posterior to the pulmonary artery.<unk>  is often accompanied by other heart defects, the most common type being intracardiac shunts such as atrial septal defect (ASD) including patent foramen ovale (PFO), ventricular septal defect (VSD), and patent ductus arteriosus (PDA). Stenosis of valves or vessels may also be present.
When no other heart defects are present it is called 'simple'<unk> ; when other defects are present it is called 'complex'<unk> .
Although it may seem counterintuitive, complex<unk>  presents better chance of survival and less developmental risks than simple<unk> , as well as usually requiring fewer invasive palliative procedures. This is because the left-to-right and bidirectional shunting caused by the defects common to complex<unk>  allow a higher amount of oxygen-rich blood to enter the systemic circulation. However, complex<unk>  may cause a very slight increase to length and risk of the corrective surgery, as most or all other heart defects will normally be repaired at the same time, and the heart becomes "irritated" the more it is manipulated.
Dextro-Transposition of the great arteries
Transposition of the great vessels
Levo-transposition of the great arteries
Dextro-transposition of the great arteries
Single ventricle
Pentalogy of Fallot
Double outlet right ventricle
Total anomalous pulmonary venous connection