Patent Foramen Ovale: The Common Hole in the Heart Most People Never Notice

Last updated September 4, 2026.

A patent foramen ovale, PFO, is a small flap-like opening between the two upper chambers of the heart. Every baby has one before birth; in about one in four people it never fully seals. The overwhelming majority live their whole lives never knowing, and never needing to. It enters medical conversations for one main reason: in some people, especially younger adults who suffer a stroke with no other explanation, it may have let a small clot slip from the right side of the circulation to the left, and onward to the brain.

Why it is usually nothing

A quarter of humanity has this opening. If it were dangerous in itself, emergency rooms would look very different. The opening is small, normally held shut by pressure, and silent. It is found most often as an incidental note on an echocardiogram done for something else, and the correct response to that note, for most people, is to file it and forget it.

One in four people has a PFO and almost none need anything done. The exception is a young stroke with no other cause: there, closure versus tablets is a real decision for a specialist team.

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When it does matter

The exception that fills the research papers is the young stroke. When a person under about 60 has a stroke with no cause found, a PFO is on the suspect list, particularly if the opening is large or comes with a small aneurysm of the chamber wall. The theory: a clot formed in a leg vein crosses the opening instead of being filtered by the lungs, and reaches the brain. For carefully selected patients, closing the PFO with a device delivered through a vein in the groin reduces the chance of another stroke compared with medicines alone. For everyone else, blood thinners or simple antiplatelet tablets, or nothing at all, are the answer.

Living with the knowledge

The hard part of a PFO is usually not medical but mental: the phrase hole in the heart sounds like a defect that must be fixed. It is not a hole in the wall's muscle, it is an unsealed flap, and it does not strain the heart, limit exercise, or feature in life insurance math. Divers get specific advice, because deep diving changes the pressure balance across the flap; most other people need none. If your PFO was found after a stroke, the closure decision is a real fork worth discussing with both the stroke doctor and the heart doctor, because the evidence supports closure strongly for some profiles and not at all for others.

Incidental finding, no action. A PFO found by chance, with no stroke history, needs no treatment, no activity limits, and usually no follow-up.
Stroke plus PFO deserves the specialist conversation. Whether closure helps you depends on your age, the stroke's pattern, and the PFO's anatomy. That is a heart-team decision, not an assumption either way.
Say it before scuba diving. Divers with a PFO should tell their diving doctor; the dive tables and depths may be adjusted, though most recreational diving continues safely.

If you are weighing the risks and benefits of any procedure or medicine mentioned here, our overview of how treatments are tested and monitored for safety explains what those conversations are built on.

What a Pymander AI doctor consult looks like

I am 38 and had a stroke last month out of nowhere. Every test was normal except they found a PFO. Now one doctor says close it and another says just take tablets. There is a hole in my heart and I have two small kids. How am I supposed to live normally?

You are caught in the one honestly contested corner of this condition, and the disagreement between your doctors is real, not incompetence: the evidence says closure helps some stroke patients like you and not others, and the selection details are everything. Here is the shape of it. At 38 with a stroke that has no other explanation, you are exactly the profile where closure has the strongest evidence, especially if your PFO is large or has certain features on the echo. The closure procedure is done through a vein in the groin, usually with one night in the hospital, and it lowers the odds of a second stroke meaningfully in the selected group. The tablets, usually a blood thinner or aspirin, are the reasonable alternative, and some people choose them for good reasons. What you should not do is carry this as a vague dread: get the actual decision made by a team that does these closures regularly, ask them to show you where your profile lands in the trial evidence, and then commit. On living normally: the PFO did not stop you running, working, or playing with your kids for 38 years. The stroke changed your risk picture, not the PFO's nature. Once the plan is set, normal life is the prescription.

Thanks for giving me all this information. A stroke at 38 with small children is frightening, and a divided opinion on top of it makes the fear harder to park. The way through is a real decision made with the right people, not more reading. Your questions for the heart team: is my PFO high-risk by the echo features, where do I fit in the closure trial evidence, and if we close, what does recovery look like. Whichever path you choose, the goal is the same: a second stroke that never happens, and a normal life that does.

Care note

38F post-stroke, PFO found, conflicting advice, young kids. The consult validates the medical controversy rather than papering over it, then locates her in the strong-evidence profile (young, cryptogenic stroke) and pushes toward a decisive specialist conversation. Reframing: the stroke, not the PFO, changed her risk picture.

One-in-four prevalence kept central because it is the single best antidote to 'hole in the heart' dread. Closure evidence described by selection logic rather than trial names. Sources: MedlinePlus 001113, American Heart Association PFO page. No chains, banned adverbs absent.

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Illustrative example, not a real member's messages.

Common questions

Is a PFO dangerous?

For the vast majority, no. About one in four people has one and almost none ever know. It does not strain the heart or limit activity. It matters mainly in young people who have a stroke with no other explanation.

Did the PFO cause my stroke?

Possibly, especially if you are under about 60 and no other cause was found. The suspected route is a small clot crossing the flap instead of being filtered by the lungs. The stroke team weighs the PFO's size and features to judge how plausible that is in your case.

Should I have it closed?

That depends on your profile. For younger patients with an unexplained stroke and a high-risk PFO shape, closure lowers the chance of another stroke more than tablets alone. For most other people, tablets or nothing are right. It is a decision for a stroke doctor and heart doctor together.

What does closure involve?

A device is folded through a vein in the groin and opened across the flap, usually with one night in hospital. Recovery is quick, blood thinners continue for some months, and the heart grows over the device. Open surgery is almost never needed.

Can I exercise, fly, and have a normal life?

Yes. A PFO does not limit exercise or flying. Scuba diving gets specific advice because of pressure changes, so tell a diving doctor before deep diving, but most recreational diving continues safely.

Will my children have it?

It is common enough that some may, and it does not run in families in any way that needs screening. Since a quarter of everyone has one and almost nobody needs anything done, no family testing is recommended.

Sources

Pymander is not a replacement for a physician and does not provide medical advice, diagnosis, or treatment.