The PFO medical abbreviation stands for patent foramen ovale, a small flap like opening between the two upper chambers of the heart that did not seal shut after birth. It is common, and most people who have one never know.
PFO usually comes up on a heart ultrasound, often during a bubble study, and in notes after a stroke without a clear cause. It is grouped with other heart findings on the diagnosis abbreviations hub. Here is what the words mean, how the finding is described on an echo report and how it differs from similar heart openings.
At a glance
Stands for
Patent foramen ovaleWord roots
Patent means open; foramen ovale means oval openingHow common
Found in roughly one in four adultsFound by
Used in
Cardiology, neurology, stroke careDo not confuse with
ASD, a true hole in the wall between the atria
What the PFO medical abbreviation means
A fetus relies on the placenta for oxygen, so circulation routes around its fluid filled lungs. Blood passes from the right upper chamber to the left through a natural opening called the foramen ovale. After birth, pressure on the left side rises and a flap usually presses the opening closed, and it seals over the following months.
In some people the flap never fully seals. It stays shut most of the time but can open briefly when pressure on the right side rises, for example during coughing or straining. That leftover opening is a patent foramen ovale. Patent here simply means open, from a Latin word for lying open.
How a PFO is found and described
A PFO is usually seen with an echocardiogram. In a bubble study, a small amount of shaken saline with tiny air bubbles is injected into a vein while the heart is imaged. If bubbles cross from the right side to the left, an opening is present. The patient may be asked to strain, like a cough, to make a flap open.
| Phrase | Meaning |
|---|---|
| Bubble study positive | Bubbles crossed between the upper chambers |
| R to L shunt | Flow from the right side to the left |
| At rest or with Valsalva | Crossing seen while relaxed or only while straining |
| Atrial septal aneurysm | A floppy, bulging wall between the atria, sometimes seen with PFO |
Why PFO comes up after a stroke
In most people a PFO causes no problems. Doctors look for it after a stroke or TIA that has no other clear cause, sometimes called a cryptogenic stroke, especially in younger adults. The concern is that a small clot from a vein could slip through the opening and travel to the brain instead of the lungs.
Neurology note: "Cryptogenic stroke, PFO found on TEE; cardiology referral to discuss closure versus medical therapy." The team is weighing whether to close the opening with a catheter procedure or to rely on medicine.
The decision depends on age, the size and features of the PFO, and other causes that have been ruled out.
PFO versus other heart openings
- ASD: atrial septal defect, an actual gap in the wall between the atria, not just an unsealed flap.
- VSD: ventricular septal defect, an opening between the lower chambers.
- PDA: patent ductus arteriosus, a fetal blood vessel that stayed open after birth.
All three share the idea of something left open, but they sit in different places and are managed differently.
Questions people ask about a PFO
A PFO finding can raise questions, especially if it was found by chance. Helpful ones include:
- Was the PFO found because of a symptom, or incidentally?
- Is it small or large, and does it shunt at rest?
- Does it change anything about my care right now?
Think of this as background on a heart finding. A cardiologist or neurologist can explain whether a PFO matters in your situation.
Frequently asked questions
What does PFO stand for on an echo report?
PFO stands for patent foramen ovale. It means the small fetal flap between the upper heart chambers did not fully seal after birth.
How common is a PFO?
It is common. Studies suggest about one in four adults has one, and most never have any symptoms or problems from it.
Is a PFO a hole in the heart?
It is often described that way, but a PFO is a flap that usually stays closed and only opens briefly. A true hole in the same wall is called an atrial septal defect.
Does every PFO need to be closed?
No. Most are left alone. Closure is considered in selected cases, such as some strokes with no other cause, after a specialist review.