ABSTRACT
Congenitally corrected transposition of the great arteries (CCTGA) is a rare defect in which the ventricles are arranged in atrioventricular (AV) discordance and, at the same time, a ventriculo-arterial discordance exists. Despite the natural disarrangement of the cardiac chambers and valves, the blood streams in normal sequence, and the flow is functionally correct. Congenitally corrected transposition evolves in embryonic development by erroneous rotation of the bulboventricular tube leftward instead of rightward. As a result, the structures derived from it are inverted. The atria and the sinus venosus remain physiologically situated. In general, CCTGA is a rare congenital heart defect, accounting for <1% of all congenital heart defects. If excluding patients with univentricular AV connection, the incidence of CCTGA is about 0.5% of all congenital heart defects. Isolated CCTGA may be first diagnosed in adulthood. In children with CCTGA, but not in adults, exercise results in an increase in right ventricular ejection fraction.
