Transposition of the Great Arteries (TGA) occurs when the two main arteries or blood vessels leaving the heart are reversed. The pulmonary artery arises from the left ventricle (instead of the right), sending oxygen-rich blood back to the lungs. The aorta arises from the right ventricle (instead of the left), sending oxygen-poor blood back to the body. This misrouting stops oxygen from being delivered to the body’s tissues and organs and can be life-threatening. The body does not receive the oxygen it needs to function properly. Babies can look blue, especially around the lips and nails. Babies can have a fast heart rate, fast breathing, and poor feeding.