Smartwatch Screening Detects More Atrial Fibrillation in High-Risk US Adults

Smartwatch-based screening significantly improves detection of atrial fibrillation (AF) in older adults at high risk for stroke, according to the EQUAL randomized trial published in the Journal of the American College of Cardiology on April 14, 2026.¹ The study evaluated whether wearable technology—specifically the Apple Watch (Apple, Inc.)—could enhance AF diagnosis compared with standard care in these patients.

The EQUAL trial was a multicenter, randomized controlled study in the Netherlands, enrolling adults 65 years or older with elevated CHA₂DS₂-VASc scores and no history of AF. Participants were assigned to smartwatch-based screening or usual care (including 12-lead electrocardiogram [ECG], Holter monitoring, in-hospital telemetry, or handheld mobile ECG devices).

The intervention group used an Apple Watch capable of passive photoplethysmography (PPG) monitoring and on-demand single-lead ECG recording. Suspected AF episodes triggered a 30-second recording, which was immediately sent for remote clinical review.

Over 6 months, AF was newly diagnosed in 9.6% of patients in the smartwatch group compared with 2.3% in the control group, with a hazard ratio of approximately 4.4. Additionally, detection occurred earlier in the smartwatch group.

Importantly, the study incorporated an automated pathway, enabling ECG review within 24 hours and prompt clinician response. This design addressed a major limitation of prior wearable studies: reliance on user activation. Previous trials were also impacted by the use of adhesive ECG patches, which were reported to cause discomfort and resulted in insufficient wear time.

In all, the combination of continuous passive monitoring and confirmatory ECG significantly improved diagnostic yield while maintaining clinical validity.

These findings position smartwatch-based AF screening as a viable tool for the early detection of undiagnosed and asymptomatic AF in high-risk patients, allowing for timely, clinician-directed treatment.

The study also highlights the importance of workflow integration. Detection alone is insufficient; rapid confirmation and clinical response are critical to translating screening into outcomes.

However, questions remain regarding long-term outcomes and downstream management. Another concern is equitable access, in terms of both technological competency and financial viability.

The EQUAL trial provides robust randomized evidence supporting smartwatch-based AF screening in adults at high risk for stroke; however, further evidence is needed to confirm the clinical benefits.

1. van Steijn NJ, Blommestijn IS, Blok S, et al. Enhanced detection and prompt diagnosis of atrial fibrillation using Apple Watch: a randomized controlled trial. J Am Coll Cardiol. 2026;87(14):1714-1728. doi:10.1016/j.jacc.2025.11.032