Patent foramen ovales (PFO) are very common. They are present in about 25% of adults. They are a tunnel-like space between layers of the wall that divides the upper chambers of the heart (the left and right atria).

Blood clots that form in the veins can make their way through patent foramen ovales into the arteries. This can cause strokes and other medical problems. For this reason, people who have had strokes usually undergo echocardiography. If a PFO is found, your doctor may recommend closing it to eliminate future risk for blood clots causing strokes in this way.

The related question is whether people who have not had strokes should have their PFOs closed. If that were the right thing to do, 25% of adults would need surgery or catheter-borne closure devices to close PFOs. Because the risk of stroke is really quite low for otherwise healthy people with PFOs, we do not recommend closure routinely.

In your case, it sounds like your PFO may be so big that it is comparable to a hole in your atrial wall. We generally recommend closing these defects. This eliminates the risk for blood clots causing strokes. It also reduces the strain on the heart due to blood circulating back through the lungs a second time through the defect. An echocardiogram will show whether this is causing strain on your heart.

Although closing the PFO can't be considered an emergency, I wouldn't put it off forever.