Key takeaways

• Syncope (fainting) accounts for around 650,000 emergency department visits in the UK every year.

• The ASPIRED trial compared a wearable ECG heart monitor worn for 14 days with standard care in patients who came to the emergency department after an unexplained syncope episode.

• Immediate ECG monitoring did not reduce recurrent syncope over one year but did improve the diagnosis and treatment of arrhythmias and was associated with lower death rates.

• These findings suggest that early monitoring should be considered as part of routine emergency department care for unexplained syncope.

Munich, Germany – 31 August 2026: Early ECG monitoring initiated in the emergency department (ED) has the potential to transform the care of thousands of patients who attend the ED with unexplained fainting. This was the main conclusion of the ASPIRED trial presented in a Hot Line session today at ESC Congress 2026¹ and published simultaneously in the New England Journal of Medicine.

Syncope (also called ‘fainting’ or ‘blackout’) accounts for around 650,000 ED visits in the UK every year.2 While most cases of syncope are benign, some are caused by potentially life-threatening cardiac arrhythmias.

“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,” said Principal Investigator of the ASPIRED trial, Professor Matthew Reed from The Usher Institute, Edinburgh, UK. “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.” 

ASPIRED was conducted at 45 hospitals in the UK. Adults with syncope that remained unexplained after an evaluation in the ED were randomised (1:1) to either 14-day ambulatory cardiac monitoring or the standard management practice of their hospital. Patients in the monitoring group were given a small waterproof, leadless non-invasive heart monitor to wear, which recorded their cardiac rhythm continuously. Participants were instructed to press a button on the heart monitor if they experienced another syncopal event. In both groups, patients were asked to record any syncopal episodes in a paper diary.

In total, 2,233 patients (mean age 58.3 years; 48% female) were analysed, making this the largest randomised trial to date assessing immediate ambulatory ECG monitoring in patients with unexplained syncope.

Regarding the primary endpoint, no significant difference was observed in the mean number of self-reported syncope episodes at one year with ECG monitoring or standard care (1.37 vs. 1.58; incidence rate ratio 0.89; 95% confidence interval 0.68 to 1.18; p=0.43).

However, monitoring more than doubled the detection of clinically significant cardiac arrhythmias (22% vs. 9%) and led to earlier diagnosis (median 22 vs. 55 days). In addition, monitoring increased the proportion of patients who received appropriate treatments including pacemaker implantation (6.8% vs. 4.6%) and anti-arrhythmic therapy (10.8% vs. 7.3%). Of note, monitoring was associated with a 50% reduction in all-cause mortality (1.5% vs. 2.9%) at one year. Patients also reported very high acceptability of the monitoring device.

“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,” summarised Professor Reed. “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.”

ENDS