Transposition of the great arteries

Transposition of the great arteries (TGA), also known as transposition of the great vessels, is a congenital cardiovascular malformation resulting from abnormal embryonic development of the aorta and pulmonary artery. The human body has two types of blood circulation: systemic circulation and pulmonary circulation. Normally, systemic circulation follows the path: "left ventricle → aorta → systemic arteries → systemic capillaries → veins → right atrium," and pulmonary circulation follows: "right ventricle → pulmonary artery → pulmonary capillaries → pulmonary veins → left atrium." TGA occurs when the right ventricle connects to the aorta and the left ventricle connects to the pulmonary artery. Clinically, TGA can be classified into two types: Corrected Transposition of the Great Arteries (CCTGA): Also known as congenitally corrected transposition of the great arteries, this is a rarer form. It is characterized by the aorta originating from the right ventricle and the pulmonary artery from the left ventricle, but with discordant atrioventricular connections: the right atrium connects to the left ventricle (which functionally serves the pulmonary circulation), and the left atrium connects to the right ventricle (which functionally serves the systemic circulation). The condition is less severe, and if not accompanied by other malformations, individuals can live into adulthood. Uncorrected Transposition of the Great Arteries (d-TGA): Also known as complete transposition of the great arteries, this is more common. It is primarily divided into two types: with or without a ventricular septal defect. It is characterized by the aorta originating from the right ventricle and the pulmonary artery from the left ventricle, with concordant atrioventricular connections: the right atrium connects to the right ventricle, and the left atrium connects to the left ventricle. It is often accompanied by other cardiovascular malformations such as patent ductus arteriosus, atrial septal defect, and ventricular septal defect. The condition is severe, and without timely treatment, most affected infants die around 1 year of age.