Question

Identify the anomaly shown in the image.

• A. Tetralogy of Fallot
• B. Total anomalous pulmonary venous return
• C. Transposition of the great arteries
• D. Truncus arteriosus

Hint:

"Transposition" means swapped positions.
In TGA, look for the Aorta originating from the RV and the PA originating from the LV, creating parallel independent circuits.

Answer 1

The Correct Option is C

Concept:
The clinical image represents a schematic of a congenital cyanotic heart defect.
The clinician must trace the anatomical origins of the major outflow tracts (aorta and pulmonary artery) from their respective ventricles to identify the anomaly.
Explanation:
• In a normal heart, the pulmonary artery (PA) arises from the Right Ventricle (RV), and the Aorta (AO) arises from the Left Ventricle (LV).

• The provided schematic clearly demonstrates ventriculoarterial discordance: the Aorta is seen arising anteriorly from the Right Ventricle, while the Pulmonary Artery arises posteriorly from the Left Ventricle.

• This specific anatomical crossing and swapping of the outflow tracts is the defining pathognomonic feature of D-Transposition of the Great Arteries (D-TGA).

• Because of this swap, the systemic and pulmonary circulations function in parallel rather than in series, which is incompatible with life unless a mixing lesion (like a VSD, ASD, or PDA) is present.

• Tetralogy of Fallot would show an overriding aorta, a VSD, right ventricular hypertrophy, and pulmonary stenosis, not a complete swap of the vessels.

• Truncus arteriosus would show a single large vessel giving rise to both systemic and pulmonary circulations overriding a VSD.
Final Answer:
The schematic shows the aorta arising from the right ventricle and the pulmonary artery from the left, which is Transposition of the Great Arteries.