Rare case of absent pulmonary valve syndrome with circular shunt.

Absent pulmonary valve syndrome (APVS) is a rare congenital cardiac anomaly, commonly associated with tetralogy of Fallot (TOF). Non-TOF variant, APVS with intact ventricular septum (IVS) and patent ductus arteriosus (PDA) are infrequently reported. While airway compression is a well-known complication, hemodynamic compromise with circular shunting is extremely rare. A full-term neonate with prenatally diagnosed APVS and IVS presented with severe pulmonary stenosis, pulmonary regurgitation (PR), tricuspid regurgitation (TR), and a large PDA. On the 3rd day of life, the infant developed respiratory distress and systemic hypoperfusion. Echocardiography revealed a circular shunt comprising severe PR and TR, right-to-left shunting at the atrial level, and left-to-right ductal flow. Emergent PDA ligation resulted in rapid hemodynamic recovery. The infant remained well at the 8-month follow-up. This appears to be the first reported case of circular shunting in APVS and intact IVS, emphasizing the need for vigilance and timely surgical intervention.