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Patent Foramen Ovale (PFO)


A patent foramen ovale (PFO) is a hole in the wall between the heart's two upper chambers (atria). Before birth all babies have this opening so that oxygen-rich blood from the umbilical cord can flow through the fetal heart and back out to the rest of the fetus's body, a job taken over by the lungs after the baby is born and starts breathing. Normally, the opening closes during infancy. But in some people, it doesn't close, a condition called patent foramen ovale, or PFO.

PFOs are common, affecting about one in four people. Because the condition usually doesn't cause symptoms, most people with a PFO never know they have it. A PFO is only a cause for concern if there are complications, such as when a blood clot goes through the opening and blocks a blood vessel leading to the brain, resulting in a stroke or the type of mini-stroke known as a transient ischemic attack (TIA). PFOs can also cause low oxygen levels in the blood, which can make you dizzy or short of breath.

Our approach to PFOs

The UCSF Adult Congenital Heart Disease Clinic provides comprehensive, highly specialized care for patients living with heart defects. Because PFOs are often discovered after someone has a stroke, our neurologists work with our heart care specialists to provide medical evaluations, advanced treatments and long-term monitoring. Our interventional cardiologists are experts in performing the minimally invasive procedure used to repair PFOs. The minimally invasive approach offers patients many benefits, including less post-op pain, a faster recovery and less scarring than heart surgery.

Signs & symptoms

Most people with a PFO have no symptoms. Some only discover they have a PFO after having an echocardiogram or heart imaging test for other reasons.

Signs that you may have a PFO include:

  • A stroke or TIA with no apparent cause, especially in people under age 55. This is the most common way patients learn they have a PFO.
  • Low oxygen levels in the bloodstream. This can happen when too much blood flows through the PFO and is pumped out to the body, instead of circulating through the lungs (where it would receive oxygen).


If you have a stroke or TIA with no clear cause, your neurologist or cardiologist may refer you for an echocardiogram (heart ultrasound) to check for a PFO. This test uses sound waves to deliver detailed images from inside your heart. Often, the evaluation is done with a bubble study, a safe and painless test in which a sterile saline (saltwater) solution is shaken up to form tiny bubbles and injected into a vein. The bubbles travel to the heart and the echocardiogram tracks their movement there. If the bubbles move from the right side of the heart to the left, this indicates an opening, or PFO, between the two chambers.


A PFO doesn't need treatment unless it has caused a problem, such as a stroke or a TIA. In that case, your doctor will recommend closing your PFO to reduce the risk of subsequent events.

PFO closure is a minimally invasive procedure performed by a specialist in interventional cardiology in our cardiac catheterization lab. You will be sedated but not completely asleep (that is, not under general anesthesia) during the procedure, which takes about an hour. The doctor makes a small incision in the groin area to access the femoral vein and inserts a catheter (a long, thin, flexible tube) that has a closure device on the tip. Guided by X-ray and ultrasound imaging, the doctor threads the catheter through blood vessels to reach the place in the heart where the PFO is located. The device is then put in place over the PFO to permanently seal the opening between the two chambers. When this repair is complete, the catheter is removed.

Following the procedure, you'll be monitored in the recovery area for approximately four to six hours. Most patients go home the same day. Before discharge, you'll have another echocardiogram to check that the closure device is in the right place.

You'll have a follow-up visit with the interventional cardiologist approximately one month after your procedure. You'll need to have regular checkups with your primary care provider and local cardiologist as well. To help prevent blood clots and reduce your stroke risk, you'll need to take a daily aspirin for six months to a year and another blood-thinning medication for at least six months. For six months after the procedure, you'll also need to take antibiotics anytime you have dental work or if you have surgery involving your bladder, stomach or lungs.

In your clinic visit before the procedure, your doctor will provide you with more detailed follow-up information.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.

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