Q20.0: Common arterial trunk

Your main artery (aorta) and pulmonary artery are fused together. This condition is congenital, which means you were born with it.

The heart pumps blood through the body. Inside the heart are 4 chambers. There are 2 heart atria and 2 ventricles. Both heart atria and both ventricles are separated from each other by a partition. Major, important blood vessels branch out of the heart. The main artery (aorta), originating from the left lower chamber (ventricle) of the heart, supplies the whole body with oxygen-rich blood. The right ventricle pumps oxygen-poor blood through the pulmonary artery to the lungs, where the blood is then enriched with oxygen.

The aorta and pulmonary artery usually separate from each other during development in the womb before birth. In your case, the aorta and pulmonary artery are still fused together. The precise cause of this is not known. This means you only have one major blood vessel branching out of the ventricles. You also have a hole in the wall (the cardiac septum) between the ventricles. This causes blood to flow out of both ventricles into your lungs and your body. This blood is a mixture of oxygen-poor and oxygen-rich blood.

With this heart defect, the body is not supplied with enough oxygen, making the skin appear bluish in color. The altered blood flow also puts the heart and lungs under greater strain than normal. You may have various symptoms as a result. This often causes rapid breathing and shortness of breath. The heart usually beats very quickly and irregularly. The symptoms may begin shortly after birth.

Additional indicator

On medical documents, the ICD code is often appended by letters that indicate the diagnostic certainty or the affected side of the body.

  • G: Confirmed diagnosis
  • V: Tentative diagnosis
  • Z: Condition after
  • A: Excluded diagnosis
  • L: Left
  • R: Right
  • B: Both sides

Further information


This information is not intended for self-diagnosis and does not replace professional medical advice from a doctor. If you find an ICD code on a personal medical document, please also note the additional indicator used for diagnostic confidence.
Your doctor will assist you with any health-related questions and explain the ICD diagnosis code to you in a direct consultation if necessary.


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