A new study published in the Journal of the American College of Cardiology shows that smartwatches significantly improve the detection of atrial fibrillation (AF) compared with standard medical care.

Researchers from Amsterdam University Medical Center analyzed data from 437 patients over the age of 65 who were at increased risk of stroke.

Half of the participants were provided with smartwatches equipped with both photoplethysmography (PPG) and electrocardiography (ECG) capabilities, while the other half received routine physician-led care. Participants were followed for six months, and those wearing the watches used them for about 12 hours per day on average.

The results were striking: among smartwatch users, 21 patients were diagnosed with atrial fibrillation and started on treatment, with 57% of them reporting no symptoms at all. In contrast, only five patients in the standard-care group were diagnosed, and all of them already had clear symptoms.

This indicates that smartwatches help identify hidden cases of arrhythmia that would otherwise go undetected.

Atrial fibrillation is a type of irregular heartbeat that increases the risk of blood clot formation. If a clot travels to the brain, it can cause a stroke.

Early diagnosis of this arrhythmia is critical, as timely treatment significantly reduces the risk of serious complications.

PPG technology measures pulse and blood flow changes through the skin on the wrist, while the ECG function records the heart’s electrical activity. Together, these provide more accurate information about heart rhythm than traditional monitoring methods, which typically rely on standard devices used only for short periods or when patients experience symptoms.

The researchers noted that smartwatches not only increase detection rates but also make monitoring more convenient and sustainable over the long term, as patients can wear the devices in everyday life for many months. This could reduce the burden on healthcare systems by enabling earlier identification of cases that might otherwise lead to severe complications and costly treatment.