Aortic arch interruption (AAI), is a rare condition present at birth in which the aortic arch does not connect the ascending aorta with the descending aorta. The aorta is the main artery leaving the heart with oxygenated blood to deliver to the rest of the body. It first travels up from the heart as the ascending aorta then "arches" around to become the descending aorta, which travels to the lower part of the body. AAI describes the lack of tissue connecting the two parts of the aorta. This is often fatal if not treated with surgery immediately at birth. Often, the condition is associated with DiGeorge syndrome, which results in poor development of many parts of the body. AAI is usually diagnosed by injecting a dye, into the arteries of the heart and viewing the results with an x-ray machine. This is called angiocardiography. Echocardiography, or an echo, as well as other imaging tests such as x-rays and CT scans are also possible.