The human heartshowhide heart defect

The human heart

Possible heart defects

Patent foramen ovale - PFO

What is it?

In patent foramen ovale (PFO), the tissue of the cardiac septum overlaps to form a tunnel-like connection between the right and left atria. With a PFO the connection between the atria is not permanent but opens only sometimes. If this happens, blood can flow from the right to the left atrium.

How does the defect occur?

In unborn children the cardiac septum is not closed completely. The so-called foramen ovale creates a connection between the two atria, thus enabling the blood to flow from the right into the left atrium. As the unborn child does not need a functional pulmonary circulation yet, the latter is bypassed by the connection between the two atria. Following birth, this connection starts to close. If this does not happen, it is called a patent foramen ovale.

How is the PFO treated?

Often the PFO is so small that it does not represent a serious problem and does not need to be corrected. The interchange of small amounts of blood between the two atria per se is not critical. However, if the PFO is larger, or if an adult patient has a tendency toward clot formation, interventional closure can make sense. 

As a rule, transoesophageal echocardiography is first performed to determine the size of the PFO. A catheter is then inserted into a blood vessel in the inguinal area and advanced into the heart. Through this cahtheter, an occluder of the right size is advanced into the heart and placed in the defect. The catheter is removed, the occluder closes the hole and becomes firmly ingrown over time. 

Here you can see how the Nit-Occlud® PFO occluder is put into place.