Patent Foramen Ovale

A patent foramen ovale (PFO) is a small, usually harmless opening between the heart's upper chambers (atria) that didn't close naturally after birth. It's a normal part of fetal circulation, but in about 1 in 4 people (25%), it remains open. Most individuals with a PFO never know they have it, as it rarely causes problems.

What is Patent Foramen Ovale?

A patent foramen ovale (PFO) is a small, flap-like opening between the two upper chambers of the heart (the right and left atria) that did not close completely after birth. This opening is a normal part of a baby's heart development before birth, but it usually seals shut shortly after. When it remains open, it is called a patent foramen ovale.

Before a baby is born, the foramen ovale allows blood to bypass the lungs, which are not yet functioning. Once the baby takes its first breaths, pressure changes in the heart usually cause this flap-like opening to close naturally and permanently. When this closure does not happen, the opening is considered "patent," meaning open. A PFO is not considered a heart defect but rather a common variation in heart anatomy. It is estimated that about 1 in 4 people (25%) have a PFO, meaning it is present in a significant portion of the general population. Most people with a PFO live their entire lives without ever knowing they have it, as it typically causes no symptoms or health issues.

Symptoms

Most people with a patent foramen ovale (PFO) experience no symptoms and are unaware they have the condition. A PFO is often discovered by chance during tests for other health concerns. When symptoms do occur, they are usually related to other conditions that a PFO might be associated with, rather than directly caused by the opening itself.

Because a PFO typically causes no symptoms, it is often found incidentally during diagnostic tests for unrelated conditions. For example, a doctor might discover a PFO during an echocardiogram performed for a different reason. While a PFO itself usually doesn't cause symptoms, it has been linked to certain medical conditions in some individuals. These associations include cryptogenic stroke (a stroke with no clear cause), migraine with aura (a type of headache accompanied by sensory disturbances), and decompression sickness in divers. It is important to understand that these are associations, and having a PFO does not guarantee you will develop these conditions.

Causes & risk factors

A patent foramen ovale (PFO) occurs when the foramen ovale, a natural opening in the heart present before birth, fails to close completely after birth. This is a natural anatomical variation, not a condition caused by anything you did or didn't do. There are no known specific risk factors that make a PFO more likely to remain open.

The primary "cause" of a PFO is simply the failure of the foramen ovale to seal shut after birth. In the womb, this opening is essential for blood circulation, allowing blood to bypass the baby's lungs. After birth, as the lungs begin to function, the pressure changes in the heart usually cause the flap to close. Researchers do not fully understand why the foramen ovale remains open in some individuals and closes in others. It is not considered a preventable condition, nor is it linked to lifestyle choices or environmental factors. Therefore, there are no specific risk factors that increase your likelihood of having a PFO. The conditions sometimes associated with PFO, such as stroke or migraine, are not risk factors for *having* a PFO, but rather potential complications or co-occurring conditions.

How it's diagnosed

A patent foramen ovale (PFO) is often discovered incidentally during tests for other conditions, as it usually causes no symptoms. Doctors typically diagnose a PFO using an echocardiogram, which is a type of ultrasound that creates detailed images of your heart and its blood flow, sometimes with a special "bubble study."

An echocardiogram is the main tool used to diagnose a PFO. This non-invasive test uses sound waves to produce moving pictures of your heart, showing its structure and how blood flows through it. A standard transthoracic echocardiogram (TTE), where the transducer is placed on your chest, can sometimes detect a PFO. To better visualize a PFO, doctors often perform a "bubble study" during an echocardiogram. In this procedure, a small amount of sterile salt water (saline) is shaken to create tiny bubbles and then injected into a vein. If a PFO is present, these bubbles can be seen crossing from the right side of the heart to the left side, confirming the opening. A transesophageal echocardiogram (TEE), where a small probe is guided down your throat, provides even clearer images of the heart and is often used for a more definitive diagnosis of a PFO, especially if a bubble study is inconclusive.

Treatment options

Most people with a patent foramen ovale (PFO) do not require any treatment, especially if they have no symptoms or related health issues. If a PFO is thought to be linked to a serious condition like a stroke, treatment options may include blood-thinning medications or a procedure to close the opening, depending on your specific health situation.

For the vast majority of individuals with a PFO, no treatment is necessary. Since a PFO often causes no problems, doctors usually recommend a "watch and wait" approach. However, if a PFO is believed to be the cause of a cryptogenic stroke (a stroke with no other identifiable cause), your doctor might discuss treatment options. These options typically include: * **Medications:** Blood-thinning medications, such as antiplatelet drugs (like aspirin) or anticoagulants, can help prevent blood clots from forming or traveling through the PFO to the brain. This is often the first line of treatment. * **PFO Closure Procedures:** In certain cases, especially after a cryptogenic stroke, a procedure to close the PFO may be considered. This is usually done using a catheter-based device, where a small device is guided through a blood vessel to seal the opening. Less commonly, open-heart surgery may be performed. PFO closure is a significant decision, and it carries potential risks, including a temporary increase in the risk of atrial fibrillation (an irregular heartbeat) or bleeding. Your doctor will discuss the benefits and risks with you to make a shared decision based on your individual circumstances, considering the evidence from studies like those reviewed by the Cochrane Library.

Recovery & outlook

The outlook for most people with a patent foramen ovale (PFO) is excellent, as it often causes no problems and requires no treatment. If a PFO is closed due to a related condition like stroke, recovery is generally good, though some individuals may experience temporary side effects or risks such as atrial fibrillation after the procedure.

For the majority of people who have a PFO and no associated health issues, the outlook is very positive. They can expect to live a normal, healthy life without any impact from the PFO. Regular check-ups with your primary care doctor are usually sufficient. If you undergo a PFO closure procedure, recovery typically involves a short hospital stay. You may experience some discomfort at the catheter insertion site. Your doctor will provide specific instructions for recovery, which may include avoiding strenuous activities for a period. Follow-up appointments and imaging tests will be scheduled to ensure the device is properly in place and the PFO remains closed. While PFO closure can be effective in reducing the risk of recurrent stroke in selected patients, it's important to be aware of potential complications, such as the risk of atrial fibrillation, which is usually temporary. Most people recover well and can resume their normal activities within a few weeks or months.

When to see a doctor

If you have a patent foramen ovale (PFO) and experience new or worsening symptoms like sudden weakness, numbness, vision changes, difficulty speaking, or a severe headache, seek immediate medical attention. These could be signs of a stroke or other serious conditions, even if you don't think they are related to your PFO.

While a PFO itself rarely causes symptoms, it is important to be aware of the signs of conditions that can be associated with it, particularly stroke. If you or someone you are with experiences any of the following symptoms, call emergency services immediately: * **Sudden numbness or weakness** in the face, arm, or leg, especially on one side of the body. * **Sudden confusion**, trouble speaking, or difficulty understanding speech. * **Sudden trouble seeing** in one or both eyes. * **Sudden trouble walking**, dizziness, loss of balance, or lack of coordination. * **Sudden, severe headache** with no known cause. These symptoms require urgent medical evaluation, regardless of whether you know you have a PFO. If you have a PFO and are a diver, discuss any concerns about decompression sickness symptoms with your doctor, such as joint pain, dizziness, or skin rash after diving. Always consult your healthcare provider if you have any new or concerning symptoms.

Frequently asked questions

Is a patent foramen ovale (PFO) a serious heart condition?

For most people, a patent foramen ovale (PFO) is not a serious heart condition. It is a common anatomical variation that usually causes no symptoms or health problems. It is only considered serious if it is linked to other conditions, such as certain types of stroke, in which case treatment may be considered.

How common is a patent foramen ovale (PFO)?

A patent foramen ovale (PFO) is quite common. It is estimated that about 1 in 4 people (25%) have a PFO. Many people live their entire lives without ever knowing they have one, as it typically doesn't cause any issues.

Can a PFO cause a stroke?

While a PFO itself doesn't directly cause a stroke, it has been associated with cryptogenic stroke (stroke of unknown cause) in some individuals. In these cases, a PFO might allow a small blood clot to pass from the right side of the heart to the left and then to the brain, leading to a stroke. However, most people with a PFO never have a stroke.

What is a "bubble study" for PFO?

A "bubble study" is a specialized test performed during an echocardiogram to help diagnose a PFO. Tiny bubbles are created by shaking sterile salt water and then injected into a vein. If a PFO is present, doctors can see these bubbles crossing from the right side of your heart to the left side, indicating an open connection.

Do I need treatment if I have a PFO?

Most people with a PFO do not need treatment. Treatment is usually only considered if the PFO is strongly suspected to be the cause of a serious event, such as a cryptogenic stroke. In such cases, treatment might involve blood-thinning medications or a procedure to close the PFO.

Can I still scuba dive if I have a PFO?

If you have a PFO and are a scuba diver, you should discuss this with your doctor. A PFO can increase the risk of decompression sickness (the "bends") because it might allow nitrogen bubbles to bypass the lungs and enter the arterial circulation. Your doctor can help you understand your individual risk and recommend appropriate precautions or diving modifications.

Sources

• MedlinePlus — Patent Foramen Ovale
• Mayo Clinic — Patent Foramen Ovale
• Cochrane Library — Patent Foramen Ovale