Prenatal Diagnosis of Congenitally Corrected Transposition of the Great Arteries (CCTGA): A Case Report

CCTGA, also known as levo- or L-loop transposition (L-TGA), double discordance, or ventricular inversion, is a rare cardiovascular anomaly with inversion of the ventricles and great arteries. In this anomaly, the right atrium communicates with the morpho- logic left ventricle, which gives rise to the pulmonary artery, while the left atrium communicates with the morphologic right ventricle, which gives rise to the aorta. Thus, atrioventricular and ventriculoarterial discordance (double discordance) exist, and although the blood flows in the normal direction, it passes through the wrong ventricular chambers. It is a unique conotruncal anomaly, in which the four-chamber view is abnormal. It may be associated with other heart disorders. In most fetuses, TGA remains undiagnosed before birth. The diagnosis of TGA can be made by care- fully and appropriately evaluating the anatomic locations of cardiac chambers and the connections between the atria, ventricles, and great arteries with high-resolution ultrasound. Patients with isolated CTGA generally present later in life with signs and symptoms related to either arrhythmias or heart failure. TGA is rarely associated with chromosomal abnormality and amniocentesis is usually not undertaken. We report a case of CTGA detected at 18 week’s gestation on screening ultrasound.