Patent foramen ovale

Learn more about the causes and complications of this condition in which a hole in the heart doesn't close the way it should after birth.

A patent foramen ovale (PFO) is a hole in the heart that didn't close the way it should after birth. The small flaplike opening is between the right and left upper chambers of the heart (atria).

As a baby grows in the womb, the foramen ovale (foh-RAY-mun oh-VAY-lee) is present in between the right and left top chambers of the heart (atria). It normally closes during infancy. When the foramen ovale doesn't close, it's called a patent foramen ovale.

Most people never need treatment for patent foramen ovale.

Patent foramen ovale occurs in about 1 in 4 people, but most people with the condition never know they have it. A patent foramen ovale is often discovered during tests for other health problems.

It's unclear what causes the foramen ovale to stay open in some people, though genetics may play a role.

Normal heart function after birth

Understanding how the heart works may help you understand the role of the foramen ovale before birth.

Your heart has four chambers that pump blood:

  • The right upper chamber (right atrium). The right atrium receives oxygen-poor blood from your body and pumps it into the right ventricle through the tricuspid valve.
  • The right lower chamber (right ventricle). The right ventricle pumps the blood through a large vessel called the pulmonary artery and into the lungs, where the blood is resupplied with oxygen and carbon dioxide is removed from the blood. The blood is pumped through the pulmonary valve, which closes when the right ventricle relaxes between beats.
  • The left upper chamber (left atrium). The left atrium receives the oxygen-rich blood from the lungs through the pulmonary veins and pumps it into the left ventricle through the mitral valve.
  • The left lower chamber (left ventricle). The left ventricle pumps the oxygen-rich blood through the body's largest blood vessel (aorta) and on to the rest of the body. The blood passes through the aortic valve, which also closes when the left ventricle relaxes.

Baby's heart in the womb

Because a baby in the womb isn't breathing, the lungs aren't working yet. That means there's no need to pump blood to the lungs. At this stage, blood bypasses the baby's lungs and uses a different path to move oxygen-rich blood from the mother to the baby's body.

The oxygen-rich blood travels from the placenta to the baby's body through the umbilical cord. In the baby's body, blood vessels connect to the umbilical cord. Oxygen-rich blood travels to the heart through the vein that drains blood from the body to the right atrium (inferior vena cava). That blood is directed across the foramen ovale and into the left atrium. From there the blood enters the left ventricle, which pumps it throughout the body.

Newborn baby's heart

When a baby's lungs begin working, blood flow through the heart changes. Now the oxygen-rich blood comes from the lungs and enters the left atrium. At this point, blood flow follows the normal route.

The pressure of the blood pumping through the heart usually forces the flap opening of the foramen ovale to close. In most people, the opening eventually closes, usually sometime during infancy.

Generally, a patent foramen ovale (PFO) doesn't cause complications. Some people with a PFO may have other heart defects.

Possible complications of patent foramen ovale may include:

  • Low blood oxygen. Rarely, a patent foramen ovale can cause a significant amount of blood to bypass the lungs, causing low blood oxygen levels (hypoxemia).
  • Stroke. Sometimes small blood clots in veins may travel to the heart. They may go through a patent foramen ovale and into the left side of the heart, where they can travel to the brain and block blood flow, causing an ischemic stroke.

Some studies have found that PFOs are more common in people with unexplained strokes and migraines with aura. However, more research is needed. Usually, there are other reasons for these conditions, and it's just a coincidence the person also has a PFO.

Usually a PFO is diagnosed when tests are done for another health concern. If your primary care doctor thinks you may have a PFO or if you've already been diagnosed with one, a doctor trained in heart conditions (cardiologist) may recommend some type of echocardiogram to get a closer look at how your heart works.

If you're diagnosed with a patent foramen ovale and you have had a stroke, your doctor may also refer you to a doctor trained in brain and nervous system conditions (neurologist).


An echocardiogram is used to diagnose a PFO. An echocardiogram shows the anatomy, structure and function of your heart.

Transthoracic echocardiogram

In this common test, sound waves directed at your heart from a wandlike device (transducer) produce video images of your heart in motion. Doctors may use this test to diagnose a patent foramen ovale and detect other heart problems.

Variations of this procedure may be used to identify patent foramen ovale, including:

  • Color flow Doppler. When sound waves bounce off blood cells moving through your heart, they change pitch. These changes (Doppler signals) are displayed in different colors on the echocardiogram and can help your doctor examine the speed and direction of blood flow in your heart.

    If you have a patent foramen ovale, a color flow Doppler echocardiogram could detect the flow of blood between the right atrium and left atrium.

  • Saline contrast study (bubble study). During a bubble study, a sterile salt solution is shaken until tiny bubbles form and then is injected into a vein. The bubbles travel to the right side of your heart and appear on the echocardiogram.

    If there's no hole between the left atrium and right atrium, the bubbles will simply be filtered out in the lungs. If you have a patent foramen ovale, some bubbles will appear on the left side of the heart.

Transesophageal echocardiogram

A patent foramen ovale may be difficult to confirm by transthoracic echocardiography. Your doctor may need to do a special type of echocardiogram called a transesophageal echocardiogram to get a closer look at the heart and blood flow through the heart.

Unlike a standard echocardiogram, in which the wand (transducer) is moved across your chest, a transesophageal echocardiogram uses a small transducer attached to the end of a probe. A doctor gently inserts the probe down the tube leading from your mouth to your stomach (esophagus). Before the procedure starts, your throat will be numbed, and you'll be given medication (sedative) to keep you comfortable.

A transesophageal echocardiogram is generally the most accurate available test to diagnose a patent foramen ovale.

Most people with a patent foramen ovale don't need treatment. If a PFO is found when an echocardiogram is done for other reasons, a procedure to close the opening usually isn't done.

However, your doctor may recommend a procedure to close the hole in your heart if you have low blood oxygen levels linked to the patent foramen ovale or if you've had an unexplained stroke.

Closure of a patent foramen ovale to prevent migraines isn't currently recommended as the first treatment. Closure of a patent foramen ovale to prevent recurrent stroke is only done after a cardiologist and neurologist have determined that closure will benefit you.


Your doctor may recommend medications to try to reduce the risk of blood clots crossing a patent foramen ovale. Blood thinners (anticoagulants) may be helpful for some people with a patent foramen ovale who've had a stroke.

Surgical or other procedures

Procedures to close a patent foramen ovale include:

  • Device closure. Doctors can insert a device that plugs the patent foramen ovale during a procedure called cardiac catherization. In this procedure, the closure device is on the end of a long, flexible tube (catheter).

    The doctor inserts the device-tipped catheter into a blood vessel in the groin and guides it into place using echocardiogram images as a guide.

    Complications are uncommon with this procedure but may include a tear of the heart or blood vessels, movement of the device, or irregular heartbeats (arrhythmias).

  • Surgical closure. A surgeon can close the patent foramen ovale by opening up the heart and stitching shut the flaplike opening. This heart surgery can be done using a very small incision and may be performed using robotic techniques.

    If you or your child is having surgery to correct another heart problem, your doctor may recommend that you have the patent foramen ovale corrected surgically at the same time.

If you know you have a patent foramen ovale, but don't have symptoms, you probably won't have any restrictions on your activities.

If you'll be traveling long distances, it's important to follow recommendations for preventing blood clots. If you're traveling by car, take breaks and go for short walks. On an airplane, be sure to drink plenty of fluids and walk around whenever it's safe to do so.

After a patent foramen ovale has been diagnosed, you'll likely have a lot of questions for your doctor. Some questions you may want to ask include:

  • What caused this to happen?
  • How dangerous is this condition?
  • What treatments are available, and which do you recommend?
  • What are the risks of a procedure to close the patent foramen ovale?
  • I have other health conditions. How can I best manage these conditions together?
  • Should activity be restricted in any way?
  • Could I have passed this condition on to my child?
  • Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?

Last Updated:

November 10th, 2021

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