Patent Foramen Ovale (PFO)

A hole in your heart may sound serious. Yet a patent foramen ovale (PFO) is common and not usually a problem. About 1 in 4 people has one, and most never know it.

Some heart conditions can include different types of holes in the heart. One example is an atrial septal defect (ASD). Both ASD and PFO are openings in the wall between the heart’s upper chambers. But they are not the same.

An ASD happens when the wall between the chambers does not form the way it should before birth. This opening is larger and may cause symptoms.

A PFO is different. Before birth, everyone has a small opening in this wall. It helps blood flow around the lungs, which are not yet being used for breathing before birth. After birth, this opening usually closes on its own.

In about 3 out of 4 people, the opening closes within the first few months after birth. When it stays open, it is called a patent foramen ovale. (“Patent” means open.)

For most people, a PFO does not cause problems and treatment is rarely needed. A small amount of blood may pass through the opening, but it usually does not affect how the heart works.

In some cases, changes in pressure in the heart can cause blood to move in a different direction. In rare cases, if a blood clot passes through the opening, it could travel to the brain and cause a stroke.

Sometimes, in people with complex congenital heart disease, a PFO can actually help the heart work better. It may allow blood to reach areas that need it.