transposition of great vesselsmedical dictionary

<embryology> A congenital cardiovascular malformation in which the aorta arises entirely from the right ventricle and the pulmonary artery from the left ventricle, so that the venous return from the peripheral circulation is recirculated by the right ventricle via the aorta to the systemic circulation without being oxygenated in the lungs.

There is an intracardiac shunt, increased pulmonary vascularity, cyanosis. The chest X-ray shows that the heart size may be normal at birth, but it gradually enlarges with a globular or egg-on-its-side appearance.

(27 Jun 1999)