What is ALCAPA?

In a normal heart, both coronary arteries arise (branch) from the aorta. In anomalous left coronary artery from the pulmonary artery (ALCAPA), something goes wrong while the heart is forming in the womb, and the left coronary artery arises from the pulmonary artery instead of the aorta. Sometimes doctors call this heart defect “anomalous origin of the left coronary artery from the pulmonary artery.” Anomalous means irregular.

When the left coronary artery is attached to the pulmonary artery instead of the aorta, two main differences in the blood flow feeding the heart occur that can quickly cause the tissue of the heart to become damaged and die:

• Not enough blood reaches the heart because of “coronary steal.” When the left coronary artery is attached to the pulmonary artery, some of the blood flowing into the coronary artery never makes it to the heart. Instead, it flows back into the pulmonary artery, which “steals” the blood from the heart.
• The blood that does reach the heart doesn’t have as much oxygen as it should. Because in ALCAPA the left coronary artery arises from the pulmonary artery, it supplies the heart muscle with deoxygenated blood. When there is less overall oxygen in the blood, the heart muscle has less oxygen to take in to feed muscle cells.

The combination of coronary steal plus lower blood oxygen leads to the starvation of the heart muscle, which can cause heart muscle damage or death.

Signs and symptoms of ALCAPA

In an infant, ALCAPA symptoms can include:

• Blue or purple tint to gums, tongue, skin and nails (cyanosis)
• Poor eating and poor weight gain
• Crying with feeds
• Rapid breathing or shortness of breath
• Profuse sweating, especially with feeding
• More sleepiness than normal
• Unresponsiveness (the baby seems “out of it”)
• Heart murmur - the heart sounds abnormal when a doctor listens with a stethoscope 

Testing and diagnosis for anomalous left coronary artery from the pulmonary artery

ALCAPA cannot be detected during pregnancy. ALCAPA is usually diagnosed in infancy, after a parent or pediatrician notices symptoms. In rare cases, the child doesn’t have noticeable ALCAPA symptoms until they are a toddler or older.

Diagnosis of ALCAPA may include: 

• Chest X-ray. This usually shows an enlarged heart.
• Echocardiogram (also called “echo” or ultrasound) – sound waves create an image of the heart. This often provides the definitive diagnosis. However, because coronary arteries are sometimes difficult to image, a cardiac catheterization and sometimes a cardiac MRI are used to help with the diagnosis.
• Electrocardiogram (EKG or ECG) – a record of the electrical activity of the heart. This may show evidence of myocardial infarction (heart attack).
• Cardiac MRI – a three-dimensional image shows the heart's abnormalities.

In many cases cardiac catheterization will also be required. In a cardiac catheterization, a thin tube is inserted into the heart through a vein and/or artery in either the leg or through the umbilicus (“belly button”).