Definition

Truncus arteriosus is a defect in the large blood vessels that leave the heart.

Normally, two large blood vessels called the aorta and pulmonary artery carry blood away from the heart. The aorta carries oxygen-rich blood from the heart to the rest of the body. The pulmonary artery carries oxygen-poor blood from the heart to the lungs. As the heart develops. a section of these two blood vessels sometimes combines together. It creates one large vessel called the truncus arteriosus. The oxygen-poor and oxygen-rich blood leaving the heart mix in this combined blood vessel. The mixed blood decreases the amount of oxygen-rich blood that reaches the body.

The defect also includes a large hole in the wall between the lower chambers of the heart.

Heart Chambers and Valves Copyright © Nucleus Medical Media, Inc.

Blood Flow Through the Heart Copyright © Nucleus Medical Media, Inc.

Causes

This problem is caused by a congenital defect. This means that the problem develops in the womb and a baby is born with it. It is not known exactly why this happens.

Risk Factors

Things that may raise the risk of this problem are:

• Chromosomal disorders, such as Down syndrome or DiGeorge syndrome
• Conditions and lifestyle factors during pregnancy, such as:
  • Viral infection, such as rubella
  • Poorly controlled diabetes
  • Alcohol use
  • Smoking
  • Taking certain medicines, such as thalidomide

Symptoms

Low oxygen levels in the body may cause symptoms such as:

• Blue or pale grayish skin color
• Fast breathing
• Irritability
• Poor feeding
• Poor weight gain

Diagnosis

The doctor will ask about your child's symptoms and health history. A physical exam will be done. A rapid heart rate may be detected during the exam.

Blood tests will be done.

Images may be taken of your child's body. This can be done with:

• Echocardiogram
• Chest x-ray

Your child's heart function may be tested. This can be done with:

• Electrocardiogram
• Cardiac catheterization

Treatment

The goal of treatment is to improve blood flow.

Medicine may be given to:

• Decrease fluid buildup
• Improve heart function

Surgery will be done right away. This may be done by:

• Creating a new pulmonary artery to carry blood to the lungs
• Creating a new aorta to carry blood to the rest of the body
• Closing the hole in the wall between the lower chambers of the heart

Lifelong heart monitoring will also be needed.

Prevention

There are no known guidelines to prevent this heart problem.