Using your smartphone to diagnose heart rhythm problems

Each year in the UK there are hundreds of thousands of visits to A&E by people who are having palpitations (the sensation of feeling your own heart beating), or who are feeling faint.

These are usually harmless and can be caused by stress, strenuous exercise, caffeine or certain medications. However, in some cases they can be caused by serious heart rhythm problems.

Diagnosing the exact underlying cause of palpitations or feeling faint in A&E is often difficult. These symptoms are temporary, so often by the time the patient has got to hospital and is seen in A&E, they have recovered and their ECG is normal.

To improve this, we helped to fund a team of researchers in 2019 led by Dr Matthew Reed at the University of Edinburgh and NHS Lothian to test the AliveCor® KardiaMobile, a smartphone-based ECG recorder, in 15 A&E departments across the UK. People experiencing palpitations or feeling faint were given the device to take home, with instructions to activate it when they feel palpitations or start feeling faint. The device then records the ECG which can be used to help diagnose the problem.

The researchers compared the results from 124 patients who received the ECG recorder with those who did not. The device enabled doctors to diagnose the cause of the palpitations in over five times as many patients than standard tests alone. Diagnoses were made more quickly and it cut the cost of diagnosis from £1,395 to £474 per person.

These results showed that this device could improve diagnosis, spare people with harmless palpitations from further anxiety, save the NHS money and, most importantly, save lives.

Using new wearable heart monitors to improve detection of abnormal heart rhythms

Fainting happens when there is a temporary reduction in blood flow to the brain. It's usually not harmful, and doesn’t mean there is a serious underlying problem, but in some cases it can be caused by a serious abnormal heart rhythm. Diagnosing whether this is the case can be difficult – it relies on being able to record an abnormal rhythm at the same time as a faint, which isn't easy to do.

So the BHF is also funding Dr Matthew Reed and his team at the University of Edinburgh to carry out a clinical trial aiming to improve diagnosis for people who attend A&E due to fainting.

Usually, by the time a person who has fainted has got to hospital they have recovered and their heart rhythm appears normal. So people with unexplained fainting are often referred for further tests, such as Holter monitoring (where an ECG monitor worn on a belt or strap, with leads connected to the chest, is used for one to three days).

But waiting for a referral can delay getting a diagnosis – and it’s important that any dangerous underlying heart problem is detected as quickly as possible to help prevent recurrent fainting episodes or other potentially life-threatening complications. What’s more, Holter monitors can be inconvenient – for example, they may get in the way when sleeping and have to be removed before showering - and often don’t detect anything in the short time period they are used.

The BHF-funded ASPIRED trial will study 2,000 people to investigate whether immediately applying a new heart monitoring patch when a person presents to A&E after fainting can help to improve diagnosis. These patches are much smaller than a Holter monitor, waterproof (so can be worn in the shower) and can monitor the heart’s rhythm for 14 days.

It’s hoped that this immediate monitoring over a longer period will help improve detection of serious heart rhythm problems in people with unexplained fainting, speeding up diagnosis and treatment, and potentially saving lives.

Emerging monitoring technologies and ‘wearables’ could transform the way we diagnose and treat heart and circulatory diseases in the future. But research is needed to determine how best to harness the potential of these devices. Before any healthcare system starts using a monitoring device, we need evidence that it can deliver improvements in patient care, and if so, which individuals benefit most and in what circumstances. Through studies like ASPIRED, the BHF is helping to accelerate progress in this area.

First published 1 June 2021