There was machinery-like murmur of the heart and the doctors said that the connection between the aorta and pulmonary artery is still openWhat structure is this?

Answer 1

This is called a patent ductus arteriosus. "Patent" means it's still open. Ductus arteriosus is a shunt between the pulmonary artery and the aorta. The ductus arteriosus normally closes at birth or shortly thereafter. If it remains open, it constitutes a left-to-right shunt, meaning oxygenated blood enters the pulmonary circuit.

It is critical that this shunt remain open in utero, as this is how fetal blood bypasses the lungs and enters the systemic circuit. After birth, however, the fetus must use the lungs to breath, and the ductus should close.