Patent foramen ovale (PFO)

This resource is information for parents and carers about patent foreamen ovale.

What is a patent foramen ovale?

A foramen ovale is a hole in the heart. It is necessary while babies are in the womb but should close soon after they are born.

If it does not close, the condition is called patent foramen ovale (PFO). PFOs are common and happen around 1 in every 4 people.

While a baby develops in the womb, there is a small opening between the 2 upper chambers of the heart (the atria). This opening is called the foramen ovale.

The purpose of the foramen ovale is to help circulate blood through the heart. A baby does not use its own lungs. Instead, it uses oxygenated blood from the mother that comes via the placenta. The foramen ovale directs the majority of the blood from the right side of the heart to the left, bypassing the lungs.

When a baby is born and the lungs begin to work, rising pressure in the left side of the heart usually causes a flap valve to seal across the foramen ovale causing it to close. Usually this happens within first few weeks or months of life.

In some babies this can take a lot longer to happen, and for others it will not happen at all. This is PFO.

Because it can take several months for a foramen ovale to close, it is classed as a normal finding in babies under 12 months of age.

What are the symptoms of patent foramen ovale?

PFO does not cause any symptoms.

How is a baby with PFO diagnosed?

Most of the time, there is no need to get a diagnosis of a PFO. However, if your doctor feels a diagnosis is necessary, an echocardiogram (scan) may be done. This is a technique that uses sound waves to image the heart.

Are there any complications with having PFO?

There are no symptoms and no complications associated with PFO in children.

PFO and strokes

There is some evidence that adults with PFO may have a higher risk of stroke.

A stroke happens when part of the brain does not get enough blood. This may happen if a clot becomes trapped in one of the arteries of the brain. Strokes can be minor or very serious.

Some people with PFO may be more likely to form blood clots. Clots may also be more likely to pass through the PFO and get stuck in the arteries of the brain.

What are the treatments for PFO?

In most cases of PFO, no treatment is needed.

What is the long-term outlook for a PFO?

The outlook for a PFO is excellent. Most people will never even realise they have a PFO.

Although stroke and migraines are possible complications of PFO in adults, they are rare.

Is there anything a baby with PFO cannot do?

The only thing your child will not be able to do if they have a PFO is go scuba diving. There is an increased risk of suffering from ‘the bends’ if you have a PFO.

If you want to go scuba diving and think you have a PFO but it cannot be seen on a standard echocardiogram, a ‘bubble test’ can be done. In this test saltwater solution is injected into a vein during the echocardiogram. The doctor then watches to see if bubbles pass between the 2 chambers of the heart. If this happens, it is a clear indication that a PFO is present.