Transposition of Great Vessels - Egg on String appearance

Egg on String appearance of the heart in Transposition of Great Vessels.Findings : Inapparent main pulmonary artery segment , increased vascularity and clinically cyanosis in a New born.
 This is the most common cardiac anomaly of a newborn with cyanosis and accounts for 55-7% of congenital cardiac malformations.It is most common in infants of diabetic mothers. It is isolated in 90% of those affected . Transposition of the Great Arteries occurs when the aota arises from the right ventricle and the pulmonary artery arises from the left ventricle. Therefore the oxygenated circulation is separated from the left ventricle. Therefore the oxygenated circulation is separated from the deoxygenated circulation except at the level of the PDA or  patent foramen ovale unless there is a defect in the atrial or ventricular septum.