Priya Sarv,  Narayanasamy Sabarish,  Nagpal Prashant

Final Pr. ID: Poster #: CR-004

Transposition of the great arteries (TGA) is typically described using the prefixes “D” and “L,” based on the position of the aortic root relative to the pulmonary trunk. In current practice, these prefixes are often applied as shorthand to define specific segmental combinations, such as “D-TGA” for concordant atrioventricular and discordant ventriculo-arterial connections, or “L-TGA” for congenitally corrected variants. However, atypical and mirror-image cases challenge the accuracy of this prefix-based terminology and highlight the need for full segmental description.

A 4-year-old boy with a background of complex congenital heart disease presented for follow-up evaluation prior to surgical intervention. He had a known history of mirror-imaged visceral arrangement and had previously undergone a bidirectional Glenn shunt for palliation of pulmonary atresia, ventricular septal defect, and atrial septal defect. Cardiac computed tomography revealed mirror-imaged atrial arrangement, with the morphologic right atrium located on the left and the morphologic left atrium on the right. The thoraco-abdominal organs were similarly reversed, including a left-sided liver and right-sided stomach and spleen. The ventricles showed D-looping with right-handed topology, with the morphologic right ventricle on the right and morphologic left ventricle on the left. The aorta arose discordantly in a rightward and anterior position relative to the pulmonary trunk, consistent with transposition physiology in this mirror-image setting.
This case demonstrates the limitations of relying solely on “D” and “L” prefixes. In this patient, the aortic root position was consistent with “D-TGA” in its original spatial sense, yet the overall physiology was that of congenitally corrected transposition due to the underlying atrioventricular and ventriculo-arterial connections. Describing the case simply as “D-TGA” would be misleading and risk miscommunication in clinical and surgical planning.
This report emphasizes that accurate diagnosis and classification of TGA require comprehensive segmental analysis, including atrial arrangement, ventricular topology, and the nature of atrioventricular and ventriculo-arterial connections. The position of the aorta should be reported separately rather than equated with transposition type. Recognition of these principles is essential to avoid confusion and ensure clarity in the management of complex and mirror-image variants of congenital heart disease. Read More

Authors:  Priya Sarv , Narayanasamy Sabarish , Nagpal Prashant

Keywords:  Cardiac CTA, Complex Congenital Heart Disease, Cardiovascular