This defect happens when the main coronary artery originates from the Pulmonary Artery instead of the Aorta. The pulmonary artery carries less oxygen in its blood, so now the muscle of the heart which is working very hard instead of getting fresh oxygenated blood it is getting blood with less oxygen.

The muscle of the heart does not like that and starts to become weaker and weaker, the muscle walls of the heart becomes thinner and thinner, and this predisposes to a condition called Cardio Myopathy (weak muscle of the heart). Because the muscle of the heart becomes weak and thin the heart will not be able to contract as strongly as it should and not enough blood will be getting to the muscles, the skin, or to the body organs to give them enough blood.

Symptoms
The baby will be weak, tired. Usually this condition is present in the first 2 months of life and the baby will be very tired during feeding, excessively sweating during feeding, taking long breaks before feeding, sometimes cries in severe pain as he feeds.

It is very important to diagnose this condition early because doctors may be to re-route the artery back to where it should be coming from (the aorta).