Congenitally corrected transposition of the great arteries


A rare birth disorder where the right atrium is connected to the left ventricle and vice versa. The position of the heart ventricles is also inverted which allows normal blood oxygenation. Symptoms generally only occur later in life or if other heart defects are present which is usually the case.


* Cyanosis * Tachycardia * Hepatomegaly * Tachypnoea * Heart murmur * Diaphoresis * Failure to thrive * Abnormal heart rhythm * Tricuspid valve regurgitation * Congestive heart failure * Impaired right ventricular function


Transposition of the great arteries results from faulty embryonic development, but the cause of such development is unknown. In transposition, oxygenated blood returning to the left side of the heart is carried back to the lungs by a transposed pulmonary artery; unoxygenated blood returning to the right side of the heart is carried to the systemic circulation by a transposed aorta. Communication between the pulmonary and systemic circulations is necessary for survival. In infants with isolated transposition, blood mixes only at the patent foramen ovale and at the PDA, resulting in slight mixing of unoxygenated systemic blood and oxygenated pulmonary blood. In infants with concurrent cardiac defects, greater mixing of blood occurs. Transposition of the great arteries occurs in approximately 40 of every 100,000 infants.


An infant with transposition may undergo atrial balloon septostomy (Rashkind procedure) during cardiac catheterization. This procedure enlarges the patent foramen ovale, which improves oxygenation by allowing greater mixing of the pulmonary and systemic circulations. Atrial balloon septostomy requires passage of a balloon-tipped catheter through the foramen ovale and subsequent inflation and withdrawal across the atrial septum. This procedure alleviates hypoxia to a certain degree. Afterward, digoxin and diuretics can lessen heart failure until the infant is ready to withstand corrective surgery (usually between birth and age 1).


Main name of condition: Ventriculo-arterial discordance, isolated