Patent Foramen Ovale

         Basic Facts

  • A patent foramen ovale (PFO) is a small opening between the two upper chambers of the heart, the right and the left atrium. 
  • PFO is present in about 25 percent of adults, but requires treatment only in certain circumstances. 
  • Although it rarely causes symptoms, PFO can lead to a heart attack or stroke by allowing blood clots to enter the bloodstream and lodge in a coronary artery or an artery in the brain.
  • Treatments for PFO that causes symptoms focus on prescribing anticlotting drugs or on sealing the opening.
Before birth, blood passes directly from the right side of the heart to the left, bypassing the lungs. Because of pressure changes at birth when the lungs begin to function, a wall is created between the upper chambers (atria) of the heart. That “wall” is called the inter-atrial septum. It consists of two “flaps,” which connect in the middle.

In most adults, those two flaps are fused together and there is no way for blood (or blood clots) to cross. In PFO, the flap persists, allowing blood (and sometimes even blood clots) to pass through. 

PFO typically only requires treatment if the patient is suspected of having a traveling blood clot called a paradoxical embolism. Treatment ranges from medications to surgical procedures.

Patent Foramen Ovale FAQ