Bubble Study

Overview

A bubble study is a test that uses ultrasound (sound waves that make pictures of the inside of your body) to watch how blood flows through your heart. A very small amount of sterile salty water (saline) is shaken until it fills with tiny bubbles, then injected into a vein in your arm. The bubbles travel to the right side of your heart, and the ultrasound shows whether any of them slip across to the left side. In a heart with no hole between its upper chambers, the bubbles are filtered out by the lungs and never reach the left side. If bubbles do appear on the left side, it can mean there is a small opening between the upper chambers of the heart, such as a patent foramen ovale (PFO) — a small flap-like opening that many people are born with and that usually causes no trouble at all. A bubble study is not a treatment. It is a quick, low-risk way of getting a clearer picture of your heart.

The test itself is not an everyday check-up test, but it is a very common and routine procedure in heart clinics. It is done thousands of times a week around the world, usually as part of an echocardiogram (an ultrasound scan of the heart).

A bubble study can be done at any age. It is most often offered to adults who have had a stroke or a mini-stroke (TIA) with no clear cause found, to people who get migraines with aura (visual zigzags or flashing lights before a headache), to people with unexplained breathlessness, and sometimes to divers or people being checked before certain heart procedures. It can also be used in children when a hole in the heart is suspected.

Symptoms

Common symptoms

• No symptoms at all — the test may be done simply to check the heart after an unclear scan or before another procedure.
• A stroke or mini-stroke (TIA) that happened without an obvious cause, which is one of the most common reasons for the test.
• Migraines with aura — headaches that come with flashing lights, zigzags or blind spots beforehand.
• Unexplained breathlessness, especially when exercising or lying flat.
• Feeling unusually tired or light-headed during activity.
• A heart murmur heard by a doctor, or a heart rhythm that feels irregular.

Symptoms in children

• Poor feeding or slow weight gain in babies.
• Breathlessness or sweating during feeds.
• Getting tired quickly when playing or crawling.
• Frequent chest infections.
• Sometimes no symptoms at all — a heart murmur may be the only clue.

Symptoms in older adults

• A stroke or mini-stroke where the usual causes have been ruled out.
• Breathlessness or tiredness that is new or getting worse.
• Dizziness or fainting spells.
• A heart murmur or irregular heartbeat picked up during a routine check.

Causes

Main causes

• A patent foramen ovale (PFO) — a small flap-like opening between the upper chambers of the heart that is present from birth and never fully closes in about one in four people.
• An atrial septal defect (ASD) — a true hole in the wall between the upper chambers of the heart.
• Other unusual connections between the right and left sides of the heart.
• Sometimes the test is done to rule these out rather than because one is expected — a normal result is just as useful.

Risk factors

• Being born with a PFO or a hole in the heart — this is present from birth and cannot be caused by lifestyle.
• Having had a stroke or mini-stroke at a younger age with no clear cause found.
• Getting migraines with aura.
• A family history of holes in the heart or congenital heart conditions.
• Some heart conditions or surgery that raise pressure on the right side of the heart.

When to see a doctor

See a doctor urgently if:

• Any stroke-like symptom, even if it passes quickly — call your local emergency number immediately.
• New or worsening breathlessness, chest pain or fainting.
• A heartbeat that feels very fast, irregular or does not settle.
• If you have been told you have a hole in the heart and you develop new symptoms.

Book a routine appointment if:

• You have been offered a bubble study and want to understand what it involves before deciding.
• You have questions about a PFO that was found in the past.
• You get migraines with aura and wonder whether a heart check is relevant for you.
• You are planning a dive, a long flight or surgery and have a known hole in the heart.

Diagnosis

A bubble study is itself the test. It is usually done in a heart clinic or hospital scanning department by a specialist sonographer (a trained scan technician), a cardiologist, or a nurse specialist. You will lie on a couch, sticky patches will be placed on your chest to record your heartbeat, and a small plastic tube (cannula) will be put into a vein in your arm. The sonographer holds an ultrasound probe on your chest and takes pictures of your heart. A small amount of salty water, shaken to make tiny bubbles, is then pushed through the tube. You may be asked to cough or to bear down as if passing a stool — this briefly changes the pressure in your heart and can make a small opening easier to see. The whole test is usually over in 20 to 30 minutes.

Tests that may be done

• Transthoracic echocardiogram — the standard ultrasound scan of the heart from the outside of your chest, which the bubble study is usually part of.
• Bubble study using agitated saline — the injection of tiny bubbles to see whether blood crosses between the right and left sides of the heart.
• Transoesophageal echocardiogram — a scan using a thin tube passed gently down the throat, sometimes used when clearer pictures are needed; this is done with sedation.
• Electrocardiogram (ECG) — a quick recording of the heart's electrical rhythm.
• Ambulatory heart monitor — a small portable recorder worn for a day or more to check for irregular heart rhythms.
• Brain imaging such as CT or MRI — often done first when someone has had a stroke, to look for the cause.

What to expect at your appointment

There is usually no special preparation. You can eat, drink and take your normal medicines unless your clinic tells you otherwise. Wear comfortable clothing that is easy to remove from the top half of your body. The test is not painful — you will feel a small pinch when the needle goes in, and some people notice a cool feeling in the arm or a brief strange taste or mild light-headedness as the bubbles pass through. These settle within seconds. Afterwards, a plaster goes on the needle site, you can usually go home straight away, and you can drive and eat normally. Results are looked at by a heart specialist and shared with you at a follow-up appointment or letter, so it helps to ask when and how you will hear back.

Treatment

A bubble study does not treat anything — it gives you and your doctor information. What happens next depends entirely on what it shows. If no bubbles cross over, the test is normal and the focus moves to other possible causes for your symptoms. If bubbles do cross, your doctor will talk with you about whether anything needs to be done. For most people nothing does, because a small PFO is common and harmless. When a PFO or hole is linked to a stroke or to troublesome migraines, the care team will discuss the options with you, including whether treating it would lower your risk enough to be worthwhile.

Self-care at home

• Keep taking any medicines you have been prescribed unless your doctor tells you to stop.
• Ask your clinic beforehand whether you need to pause any medicine, especially blood thinners.
• Bring a list of your medicines and any allergies to the appointment.
• Arrange for someone to come with you if you feel anxious, and ask if sedation might be used — if so, you may be advised not to drive home.
• Keep the needle site clean and check it for a day or two.
• Note down your questions before the appointment so you do not forget them.

Medical treatments

If a hole in the heart is found, treatment is not always needed. When it is, doctors may consider medicines that make the blood less likely to clot, to lower the chance of a stroke — your doctor will explain the benefits and drawbacks of this for you personally, and the choice depends on your age, other health conditions and what your scan showed. For some people with a PFO and an unexplained stroke, a procedure to close the opening with a small device passed through a tube in the groin may be discussed. Migraine treatment is a separate area and is managed by your own doctor or a headache specialist. Any decision is made together with you, and it is completely fine to ask for time to think or to request a second opinion.

When is surgery considered?

A procedure to close a PFO or a hole in the heart is only considered for some people — for example, certain adults who have had a stroke with no other cause found, or people with a large hole causing breathlessness or strain on the heart. It is done by a heart specialist using a thin tube passed through a vein in the groin up to the heart, and most people go home the next day. It is not needed for most people with a PFO, and many people live their whole lives with one without any treatment.

Living with this condition

For most people, having a bubble study changes very little day to day. You may have a follow-up appointment to discuss results, and possibly a repeat scan in the future. If a small PFO is found and nothing needs to be done, you can carry on with work, exercise, travel and hobbies as normal. If you have been given medicine to lower your stroke risk, take it as prescribed and keep up with any check-ups.

Lifestyle tips

• Stay active — regular movement is good for your heart and circulation.
• Do not smoke, and get help to stop if you do — this is one of the biggest things you can do for your heart and brain.
• Keep alcohol within the recommended limits for your country.
• Keep blood pressure and cholesterol in a healthy range, and go to any routine checks offered.
• If you dive or fly often and have a known hole in the heart, ask your doctor for advice specific to you.
• Know the warning signs of stroke, so you can act fast if they ever appear.

Diet and exercise

Eating a balanced diet with plenty of vegetables, fruit, whole grains, beans and fish, and cutting down on very salty and highly processed foods, supports heart and brain health. Regular activity — aiming for something that makes you slightly warm and out of breath most days — is safe for almost everyone with a PFO. If you have other heart conditions or you have been told to limit activity, follow your care team's advice. There is no special diet for a PFO, and no food or exercise causes one.

Mental health and emotional wellbeing

It is very normal to feel anxious before or after a heart test, and hearing words like 'hole in the heart' can be frightening even when the news is reassuring. Some people find their mind keeps returning to it, or they worry about having another stroke. These feelings usually settle once results are explained clearly, but they deserve attention too. Talking to your doctor, a nurse, or a counsellor can help, and it is fine to say you are struggling. If you ever feel overwhelmed or in crisis, contact your local emergency number or a local crisis support line straight away — you do not have to cope alone.

Prevention

You cannot prevent a PFO or a hole in the heart — it is something people are born with, and nothing you did or did not do caused it. What you can do is look after your overall heart and brain health, which lowers the chance of a stroke whatever your heart shape. A bubble study is not a screening test that everyone needs; it is used when there is a specific reason to look.

Screening programmes

A bubble study is not a routine screening test for the general public. It is offered when a doctor has a specific question to answer, such as after an unexplained stroke or mini-stroke. If you are unsure whether you should be tested, ask your own doctor — they can explain whether it would change anything for you.

Complications

If left untreated

• Most people with a PFO have no complications at all, whether or not the test is done.
• In a small number of people, a PFO is linked with a higher chance of stroke, because a tiny clot can pass from the right side of the heart to the left and travel to the brain.
• Some people with a PFO also get migraines with aura, and occasionally these improve if the opening is closed.
• A large hole in the heart that is left alone can, over many years, put extra strain on the heart and lungs — this is why some holes are monitored or closed.
• Not having the test simply means the question you and your doctor had stays unanswered; the test itself carries very little risk.

Long-term outlook

The outlook after a bubble study is usually very good. The test is short, safe and well tolerated, with only minor after-effects for most people, such as a small bruise where the needle went in. Most people are reassured by the results, and even when a PFO is found, the great majority need no treatment and live completely normal lives. If something does need attention, it is good to have found it early, when it can be discussed and managed calmly with your care team.

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