What you have described is known as Transposition of Great Arteries. In this congenital heart defect, the aorta originates from the right ventricle and the pulmonary artery from the left ventricle, resulting in two separate circulations. In order for the infant born with transposition of the great arteries to survive, they must have some communication between the right and the left sides of the heart to allow oxygen rich blood to reach the body. This mixing of blood is possible through any of the following: ASD, VSD, PDA. Even though there is mixing of oxygenated and de-oxygenated blood, it is often not adequate to sustain life for an extended period of time. Treatment consists of either the switch operation whereby the arteries are switched and surgically corrected or the atrial switch whereby the atria are switched so that right atrium connects to the left ventricle and the left atrium connects to the right ventricle. For patients with no communication between the two circulations, a temporary connection is made between the 2 atria known as the Rashkind's procedure till corrective surgery can be done.