Truncus arteriosus
Truncus arteriosus is a congenital heart defect. At birth, the heart has only one blood vessel and one valve, instead of the usual two arteries and two valves. It is always associated with a ventricular septal defect, which is a hole in the partition that separates the two ventricles.
The single output vessel from the heart means that oxygenated blood is mixed with unoxygenated blood and then enters the lungs and the rest of the body. The arteries that supply the whole body and the lungs originate from this single vessel. The subsequent increased volume of blood that enters the lungs may result in congestive heart failure and lung damage.

Symptoms
The most common symptoms of truncus arteriosus are:
- cyanosis (a blueish cast to the skin)
- fatigue
- a pallid complexion
- rapid heart rate and breathing
Who is affected by truncus arteriosus?
It is a rare heart disorder that affects fewer than 1 in 10,000 children and both genders are affected equally. It may be related to chromosome abnormalities such as DiGeorge syndrome, also known as 22q11 deletion.
Diagnosis
Truncus arteriosus is diagnosed via echocardiogram, either prenatally or during the first few hours of life. This is usually sufficient to mean that further diagnosis and tests are not required.
Typical treatment
It is repaired during prenatal surgery, during which the two circulations are separated and a conduit inserted into the pulmonary artery. The ventricular septal defect will also be closed.
Most children who undergo surgery recover and go on to develop normally.
In some cases further procedures may be necessary once the child reaches adulthood.