Causes

Researchers aren't sure what causes most congenital heart disease, which develops in the womb. Heredity might play a role in some congenital heart disease.

How the heart works

The heart is divided into two chambers on the right and two on the left. To pump blood through the body, the heart uses its left and right sides differently.

The right side of the heart moves blood to the lungs through certain blood vessels (pulmonary arteries). In the lungs, blood picks up oxygen and then returns to the left side through the pulmonary veins. The left side of the heart then pumps the blood through the aorta and out to the rest of the body.

Congenital heart disease can affect any of the heart's structures, including valves, chambers, the wall of tissue that separates the chambers (septum) and arteries.

Why congenital heart disease resurfaces in adulthood

For some adults, problems with their heart defects arise later in life, even if treated in childhood. Repairing defects improves heart function, but might not make the heart completely normal.

Even if the treatment you received in childhood was successful, a problem can occur or worsen as you age. It's also possible that problems in your heart, which weren't serious enough to repair when you were a child, have worsened and now require treatment.

Then there are complications of childhood surgeries to correct congenital heart disease that can occur later, such as scar tissue in your heart that contributes to an abnormal heart rhythm (arrhythmia).