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Patent Foramen Ovale or Atrial Septal Defect

PFOThis is a small hole between the top two chambers of the heart (the atria).

This condition occurs in approximately 15% of all people.

Usually undetected, if the hole is large enough, it can lead to blood with oxygen mixing with blood that has not yet received oxygen from the lungs. Can also cause pressure overload on the right side of the heart due to shunting of blood from the higher pressure left atrium into the lower pressure right atrium.


  • Usually these are asymptomatic and found accidentally on cardiac ultrasound.
  • There is some evidence that there may be a higher association of stroke in patients with PFO/ASD’s.
  • There is weak evidence of association of PFO/ASD with migraine headaches.

Diagnostic Tests


  • Usually no treatment is needed.
  • If a patient has had a stroke and they have a PFO/ASD they likely should be on aspirin daily.
  • Rarely, closing the hole with a catheter procedure may be warranted, but usually this is unwarranted.

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