Supermarket trolleys may be known for their wonky wheels and rusty frames, but researchers say the carts could be used to save lives by helping to identify people at risk of stroke through sensors in their handles.

According to the British Heart Foundation, one in 45 people in the UK are living with atrial fibrillation (AF), which causes an abnormal heart rhythm and can increase the risk of stroke. While people may be unaware they have the condition, early detection and diagnosis is important as treatments are available.

Now researchers have come up with an inventive approach to identifying those at risk: installing electrocardiogram (ECG) sensors in the handles of supermarket trolleys to screen adults for abnormal heart rhythms as they shop.

The trial, carried out at four Sainsbury’s supermarkets over three months, involved 2,155 adults.

Participants were instructed to hold the trolley handle for at least 60 seconds. If the sensors picked up signs of AF, a red cross flashed up on the trolley’s handle, while a green tick showed if no signs were detected. In a further screening measure, all participants were given a pulse check.

The results, presented on Friday at Acnap 2023, a scientific congress of the European Society of Cardiology, revealed that when ECG data for 220 participants who consented to have their data analysed and were flagged as potentially having AF were considered by a cardiologist, 59 participants were diagnosed as having the condition – 39 of whom were previously unaware they were affected, and were subsequently contacted to arrange a cardiology appointment.

Prof Ian Jones of Liverpool John Moores University, an author of the study, challenged the idea that some communities were hard to reach.

“My response is they’re not hard to reach; we’re just difficult to access,” he said. “By adopting this kind of approach [to health screening], we’ve become more accessible, and therefore we’re much more likely to identify healthcare problems.”

However, the team said further work was needed to improve the accuracy of the approach, noting that 20% of the 220 ECGs were unclear, typically because hand movements complicated readings. In addition, while the method correctly identified between 70% and 93% of the time those with AF, it was less accurate at spotting those without the condition: overall, the team estimated that only a quarter to a half of those flagged as having AF actually had the condition when reviewed.

Prof Jonathan Mant, the head of the cardiovascular research group at the University of Cambridge and who was not involved in the work, said there was no population screening for AF in the UK as there were uncertainties as to whether doing so would be beneficial. That is because there is a potential for screening to identify people with occasional episodes of unusual heart rhythm for whom medication may do more harm than good.

While Mant described the supermarket trolley approach as innovative, he said the number of unclear ECGs was quite high, and there was a risk that shoppers with very occasional heart-rhythm irregularities that may not require treatment could be diagnosed with AF as a result of the frequency with which they used the trolleys.

He also noted that those flagged by the sensors as having AF would need timely attention by a medical professional to check the diagnosis, possibly putting an extra burden on the health service.

Robert Storey, a professor of cardiology at the University of Sheffield, stressed the need for further assessment of those flagged by the system, but welcomed the research, noting while there had been a lot of interest in wearable devices to detect AF, many people did not have access to such gadgets.

“Consequently, the idea of allowing people to monitor their heart rhythm using a shop trolley seems an excellent idea that is worth exploring,” he said. “The results of this study show an impressive number of people having AF picked up for the first time and this could potentially prevent some of these people having a stroke.”