Complications

The abnormal heart structures of truncus arteriosus result in severe problems with blood circulation.

Because the ventricles aren't separated and all blood exits from a single vessel, the oxygen-rich blood and the oxygen-poor blood mix — resulting in blood that doesn't carry enough oxygen. The mixed blood flows from the single large vessel to the lungs, the arteries of the heart and the rest of the body.

If your baby has truncus arteriosus, the abnormal circulation of blood usually results in:

• Respiratory problems. Too much blood flows into the lungs, and the excess fluid makes it difficult for your baby to breathe.
• High blood pressure in the lungs (pulmonary hypertension). Increased blood flow to the lungs causes the lungs' blood vessels to narrow, increasing blood pressure in the lungs and making it increasingly difficult for your baby's heart to pump blood into the lungs.
• Enlargement of the heart (cardiomegaly). Pulmonary hypertension and the increased blood flow through the heart force your baby's heart to work harder than normal, causing it to enlarge. The enlarged heart gradually weakens.
• Heart failure. The increased workload and poor oxygen supply also result in weakening of your baby's heart. These factors can contribute to heart failure, the inability of the heart to supply the body with enough blood.

Complications later in life

Even with successful surgical repair of the heart during infancy, other complications associated with truncus arteriosus can occur later in life:

• Progressive pulmonary hypertension
• Leaky heart valves (regurgitation)
• Heart rhythm disturbances (arrhythmias)
• Problems related to prior operation

Common signs and symptoms of these complications include shortness of breath when exercising, dizziness, fatigue, abdominal swelling, swelling in the legs and feet, and a sensation of rapid, fluttering heartbeats (palpitations).

Truncus arteriosus in adults

In rare cases, a person with truncus arteriosus can survive infancy without surgical repair of the heart and live into adulthood. However, people with this condition will almost certainly develop heart failure and pulmonary hypertension (Eisenmenger syndrome).

This syndrome is caused by permanent lung damage from pulmonary hypertension that results in much of the blood flow bypassing the lungs entirely.