A term neonate develops cyanosis shortly after birth. Echocardiography reveals a large PDA. The radiograph shows reduced pulmonary vascularity. The oxygen saturation is 72% in the right hand and 70% in the right foot. Which additional congenital heart defect is MOST likely coexisting?

• A ASD secundum
• B Transposition of great arteries
• C Total anomalous pulmonary venous connection (TAPVC) obstructive type
• D Pulmonary atresia with intact ventricular septum ✓

Explanation

Pulmonary atresia with intact ventricular septum (PA-IVS) depends entirely on a PDA for pulmonary blood flow, explaining the large PDA. Reduced pulmonary vascularity is characteristic. The saturation being similarly low in upper and lower limbs argues against TGA where differential cyanosis (higher in lower extremities) is seen. TAPVC obstructive type shows pulmonary venous congestion with ground-glass radiograph. ASD alone does not cause this clinical picture in a neonate.

Reference: Ghai Essential Pediatrics, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.