Table 2.

Echocardiographic principles in the diagnosis of patent ductus arteriosus

Questions to be answered	Echocardiographic measurements
Is the ductus patent?	Demonstration of PDA
If the ductus is patent, how wide is it?	Specification of the size of PDA
What is the direction of the flow in the ductus?	Demonstration of loading in the left heart and increased pulmonary circulation
What is the importance of shunt?	Demonstration of systemic hypoperfusion due to ductal steal
How does it affect the pulmonary and systemic circulation?
Can the ductus close spontaneously?

PDA: patent ductus arteriosus