Fainting sends around 650,000 people to hospital emergency departments in the UK every year. Most cases turn out to be harmless, but a small number are caused by dangerous heart rhythm problems that can go undetected for weeks or even months. Now a major new trial has found that fitting patients with a simple wearable heart monitor as soon as they arrive at A&E could dramatically speed up diagnosis and even save lives.
The results of the ASPIRED trial were presented at the ESC Congress 2026 in Munich on 31 August and published in the New England Journal of Medicine.
Why Fainting Is So Tricky to Diagnose
Fainting (known medically as syncope) is one of those problems where the cause often disappears before doctors can catch it. Heart rhythm disturbances that trigger blackouts frequently come and go, so by the time someone reaches hospital, everything can look normal. Patients are often sent home with no clear answer and may then wait a long time for follow-up tests.
Principal Investigator of the trial, Professor Matthew Reed from The Usher Institute in Edinburgh, explained: “It can be difficult to determine the cause of syncope in the ED as many rhythm disturbances occur intermittently and are no longer present by the time patients arrive in hospital. Some patients then have to wait weeks or even months for investigations. Prior to the trial, preliminary evidence suggested that cardiac monitoring, initiated during the ED visit, was beneficial for detecting arrhythmias. The ASPIRED trial therefore evaluated whether fitting patients with a 14-day ECG monitor immediately after ED assessment could improve their clinical outcomes.”
How the Trial Worked
ASPIRED was carried out at 45 UK hospitals and involved 2,233 adults with an average age of 58, about half of them women. It is the largest randomised trial ever to look at using ambulatory ECG monitoring right from the emergency department for people whose fainting had no clear cause.
Half of the patients were fitted with a small, waterproof, leadless heart monitor that they wore for 14 days. The device continuously recorded their heart rhythm, and patients could press a button on it whenever they had another fainting episode. The other half received their hospital’s usual care. In both groups, patients kept a paper diary of any blackouts they experienced.
What the Study Found
There was no significant difference between the two groups in how often patients fainted again over the following year. The main aim of the trial (reducing recurrent fainting) was not met.
But the monitoring group saw major benefits in other areas.
- Better detection: Clinically significant heart rhythm problems were spotted in 22% of monitored patients compared with just 9% of those receiving standard care, more than double the rate.
- Faster diagnosis: When arrhythmias were found, the diagnosis came much sooner, with a median of 22 days compared with 55 days under standard care.
- More timely treatment: More patients in the monitoring group received the right treatment, including pacemakers (6.8% vs. 4.6%) and anti-arrhythmic medication (10.8% vs. 7.3%).
- Lower death rates: Perhaps most strikingly, patients in the monitoring group were about half as likely to die from any cause within a year of their emergency visit (1.5% vs. 2.9%).
Patients also said they liked the device and found it easy to wear.
What This Could Mean for A&E Care
The findings suggest that a small, easy-to-use monitor, fitted before a patient even leaves the emergency department, could help doctors pick up dangerous heart problems far sooner than they do now. That means fewer weeks of anxious waiting, faster access to treatments like pacemakers, and, potentially, lives saved.
Professor Reed summed it up: “Although immediate ECG monitoring did not reduce recurrent fainting, it enabled earlier identification of serious cardiac rhythm disorders, allowing patients to receive treatment much sooner, reducing uncertainty and anxiety, and potentially preventing avoidable deaths. These findings suggest that early monitoring should be considered as part of routine ED care for patients with unexplained syncope, while further research explores the observed survival benefit.”
Given the sheer number of fainting-related hospital visits in the UK each year, a shift like this could have a substantial impact, both for patients desperate for answers and for a healthcare system that badly needs quicker, clearer pathways for people who arrive at A&E without a diagnosis.