Sending adults home from the emergency department with a 14-day wearable heart monitor after an unexplained fainting spell did not reduce how often they fainted again over the following year. That is the ASPIRED trial, run at 45 UK hospitals and published on 31 August 2026 in the New England Journal of Medicine. It missed the outcome it was designed to measure.
Key takeaways
- 2,234 adults whose fainting was still unexplained after an emergency department workup were randomly assigned to a 14-day wearable monitor or to their hospital’s usual practice.
- It did not reduce repeat fainting at one year, which was the trial’s primary outcome.
- The monitored group logged 49 adverse events against 8 with standard care, with one serious adverse event in each group.
What the study found
ASPIRED enrolled adults whose fainting was still unexplained after an emergency department workup, according to the report published in the New England Journal of Medicine. A total of 2,234 patients were randomly assigned, half to a small waterproof leadless monitor worn for 14 days and half to their hospital’s usual practice. Mean age was 58.3 years and 52.1% were male. After excluding people who completed no follow-up, 1,970 were in the main analysis.
The primary outcome, the mean number of patient-reported fainting episodes at one year, was 1.37 with monitoring and 1.58 with standard care. That is about 11% fewer episodes (incidence rate ratio 0.89), but the results compatible with the data run from roughly 32% fewer episodes to 18% more (95% confidence interval 0.68 to 1.18). A gap this size turns up by chance about 4 times in 10 (P = 0.42), so it counts as no difference.
Monitoring was not free of downsides. The journal report counted 49 adverse events in the monitored group against 8 with standard care, with one serious adverse event in each. The British Heart Foundation funded the trial and Boston Scientific supplied the monitors.
Dr. Kumar’s take
The honest headline here is a negative one. ASPIRED was built to count fainting episodes, and on that measure the monitor made no difference: 1.37 episodes per patient against 1.58, with a range of possible true effects wide enough to include a worthwhile benefit and a modest harm. A trial that misses the outcome it was designed to measure has not shown that the intervention works, however sensible the idea sounds. Headlines that turn a wearable patch into a life-saver are running ahead of what this study reports.
The finding I would defend is the boring one. Unexplained fainting is currently managed by sending someone home and waiting for the event to repeat, ideally while they are wearing something that records it. The ESC notes that some patients wait weeks or even months for investigations, living in the meantime with an unexplained loss of consciousness and often told not to drive until someone works out why. A monitor already on the chest when the next episode happens is the most direct way to answer that question, and that argument stands on its own, separate from whether the episodes themselves become less frequent.
This fits a pattern elsewhere in cardiology, where moving measurement out of the clinic catches what a single office visit misses. Home blood pressure monitoring showed a similar advantage, for the same reason: intermittent problems do not schedule themselves around appointments.
More monitoring is also not free. Every extra recording that gets read is a chance to catch something that mattered, and a chance to catch a blip that would never have caused harm and act on it anyway. This trial reported more adverse events in the monitored arm and no reduction in fainting, which is why the question of what all that monitoring bought is a fair one.
What it means for you
If you have fainted without a clear cause and left the emergency department without answers, asking about ambulatory ECG monitoring is reasonable. In this trial it did not make repeat fainting any less likely, so treat it as a way to try to capture the rhythm during an episode, not as a treatment.
If you are offered a monitor, wear it properly and press the button when something happens. The design depends on capturing an event while it is occurring.
Do not read this as evidence that a consumer smartwatch replaces a medical evaluation. ASPIRED tested a prescribed 14-day medical-grade monitor, started after an emergency workup, in people already flagged as having something unexplained.