In which condition would you expect to find a "machinery type" murmur?

A "machinery type" murmur is a characteristic finding associated with Patent Ductus Arteriosus (PDA). This type of murmur arises due to the continuous flow of blood through the ductus arteriosus, an abnormal persistence of this fetal structure after birth. As the ductus remains open, blood flows from the higher-pressure aorta to the lower-pressure pulmonary artery throughout the cardiac cycle, leading to a distinctive sound that has been historically described as resembling machinery.

In the context of neonatal care, recognizing a machinery-type murmur is crucial for diagnosing PDA, as it can significantly impact the circulatory system and overall health of the newborn if not addressed. Management of a PDA may require medical or surgical intervention, particularly if the murmur is accompanied by signs of heart failure or increased respiratory distress.

While the other conditions mentioned can produce various murmurs, they do not typically generate the continuous "machinery" quality that is indicative of PDA. For instance, an atrial septal defect may produce a systolic ejection murmur related to increased blood flow across the pulmonary valve, but it does not have the continuous nature characteristic of a PDA.