Anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare heart defect.

Normally, the left coronary artery carries oxygenated blood to the heart muscle. The oxygenated blood comes from the aorta.

With ALCAPA, the left coronary artery is not connected to the aorta. Instead, it is connected to the pulmonary artery. This means that the blood does not have enough oxygen in it from the lungs. With this defect, the heart muscles receive blood that is low in oxygen. The blood also leaks back into the pulmonary artery because of the low pressure in this artery.

The Coronary Arteries
si1902_the coronary arteries
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ALCAPA may be detected in newborns. In some cases, it may not be detected until the baby is aged 2-6 months. Rarely, it is diagnosed in older children.

ALCAPA is a congenital defect. This means that the baby is born with it. It is not known why the left coronary artery develops abnormally.