Apple Watch beats standard care: Four times more atrial fibrillation detected

Anna Sandner

26.1.2026

Translation: machine translated

Smartwatches with ECG function detect atrial fibrillation in older patients four times more frequently than standard care. A new study shows: Success depends on clinical workflows - and involves many false alarms.

Smartwatches with optical pulse measurement and ECG function, such as the Apple Watch, can detect atrial fibrillation in older patients at risk significantly more often than standard care. In a new study from the Netherlands, the diagnosis was made around four times as often in the smartwatch group - albeit with greater organisational effort to check the smartwatch readings and with typical limitations of the technology (keyword: false alarm).

Smartwatch screening versus standard care

A total of 437 people aged 65 and over with an increased risk of stroke took part in the study. Of these, 219 were randomly assigned to the Apple Watch group, while the remaining 218 received standard care without a smartwatch. Whereby standard care means that the participants only sought medical advice as required and in the event of symptoms. The participants in the smartwatch group wore the watch on a daily basis for six months, for an average of twelve hours a day.

In the video interview with JACC, first author Nicole J. van Steijn explains that the watch was integrated into a clinical process. If the patients had symptoms or the smartwatch recognised irregularities, they reported this to the medical staff looking after them. Submitted ECGs were then checked within 24 hours. This interaction between the consumer device and medical evaluation was crucial for the wearable screening to work.

Results: more diagnoses, even without symptoms

After six months, the researchers diagnosed atrial fibrillation significantly more frequently in the smartwatch group than in the control group: 21 compared to five cases. Strikingly, 57 per cent of the cases detected in the smartwatch group showed no symptoms. These patients would probably not have had themselves examined without screening. In standard care, diagnoses were only made in symptomatic individuals.

Screening therefore primarily makes cases visible that would otherwise remain undetected.

What does this mean for care?

Atrial fibrillation increases the risk of stroke because the irregular atrial rhythm favours blood clots that can travel to the brain. Study leader and cardiologist Michiel Winter explains: «Our results suggest that the risk of stroke can be reduced through screening - to the benefit of patients and the healthcare system, including through lower costs.»

However, the study also shows that the real progress may lie less in the smartwatch itself than in speeding up the diagnostic process. Structured processes, clear responsibilities and fast analyses are crucial. This was guaranteed in the study. For other healthcare systems, screening only makes sense if the subsequent clarification is organised reliably, quickly and scalably.

Limitations and unanswered questions

Firstly, false alarms are a key problem. In the study, the smartwatches reported a suspected atrial fibrillation in 72 participants, but only 21 of them were actually confirmed. A large proportion of the alarms led to additional diagnostics without the suspicion being confirmed in the end. Not to mention the unnecessary worrying of those affected.

Secondly, the study addressed a clearly defined high-risk group: people over the age of 65 with an increased risk of stroke. Screening recommendations cannot automatically be derived from this for younger or lower-risk groups.

Thirdly, the study primarily measured how often atrial fibrillation was recognised and diagnostically confirmed. Whether screening ultimately prevents strokes has yet to be shown.

Anna Sandner

Senior Editor

Anna.Sandner@galaxus.de

Science editor and biologist. I love animals and am fascinated by plants, their abilities and everything you can do with them. That's why my favourite place is always the outdoors - somewhere in nature, preferably in my wild garden.

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