In truncus arteriosus, one large vessel comes out of the heart, instead of two separate ones. There's also usually a hole in the wall between the lower heart chambers, called the ventricles. The hole is called a ventricular septal defect. In truncus arteriosus, oxygen-rich blood, shown in red, and oxygen-poor blood, shown in blue, mix together. The mixed blood is shown in purple. It doesn't contain enough oxygen for the body's needs.
Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.
Check out these best-sellers and special offers on books and newsletters from Mayo Clinic Press.
Benefactor support fuels Mayo Clinic’s groundbreaking research. Make a gift today to help us save lives.