Smartwatch AF screening: what the EQUAL trial found

In the EQUAL trial, smartwatch monitoring found new atrial fibrillation in 9.6% of high-risk over-65s vs 2.3% with standard care. What it shows.

By Hydra Editorial

In the EQUAL randomised trial, high-risk older adults who wore a smartwatch were diagnosed with new atrial fibrillation (AF) far more often than those under standard care: 9.6% versus 2.3% over six months. The trial, published in the Journal of the American College of Cardiology in January 2026, tested detection. It was not designed to show whether finding AF earlier prevents strokes.

Does a smartwatch detect more atrial fibrillation than standard care?

In this population, yes. EQUAL randomised 437 Dutch adults (mean age 75, 46.7% women) with elevated stroke risk and no known AF to wear an Apple Watch (Series 5 or 8) or to receive standard care, and followed them for six months, according to TCTMD’s report.

New AF was diagnosed in 21 people (9.6%) in the smartwatch group and 5 (2.3%) in the control group. That is an absolute difference of 7.3 percentage points (hazard ratio 4.40), or a number needed to screen of 14, per the ACC journal scan.

Watch recordings flagged for review were not diagnoses in themselves. Of 37 flagged recordings, 20 (54%) were confirmed as clinical AF. About 57% of the AF episodes found by watch came without symptoms, while every case in the control group was symptomatic.

What does the EQUAL trial not show yet?

It does not show that screening prevents stroke. The investigators describe the study as underpowered for clinical outcomes: two major adverse events occurred in each group, and emergency department visits were 5.9% with the watch versus 8.3% without, a difference that was not statistically significant.

The population was also specific: older adults with elevated stroke risk. The findings say less about younger, lower-risk wearers.

The open question is what happens after detection. The investigators point to ongoing trials, REGAL and SAFER, that are expected to test whether treating screen-detected AF reduces stroke, heart failure or cognitive decline.

The same pattern appears across wearable research: signals such as a rising resting heart rate are detectable well before they are interpreted. Detection is the first step, and the value depends on what the signal is compared against.

The bottom line

  • In 437 high-risk adults over 65, smartwatch monitoring found new AF in 9.6% versus 2.3% with standard care (hazard ratio 4.40, number needed to screen 14).
  • About 54% of flagged recordings were confirmed as AF, and roughly 57% of watch-detected episodes had no symptoms.
  • Whether earlier detection reduces stroke or heart failure is not yet established; the trial was underpowered for those outcomes.

Frequently asked questions

Can a smartwatch diagnose atrial fibrillation?
In EQUAL, watch recordings flagged possible AF, and 54% of the flagged recordings (20 of 37) were later confirmed as clinical AF. The watch worked as a screening tool that led to a clinical diagnosis, not as a diagnosis on its own.
Does finding AF earlier prevent strokes?
That is not yet established for screen-detected AF. EQUAL measured diagnoses over six months and was underpowered for clinical outcomes such as stroke. The investigators point to ongoing trials, REGAL and SAFER, to address whether treatment after screening improves outcomes.

Sources

  1. [author list to be supplied], 2026. Enhanced Detection and Prompt Diagnosis of Atrial Fibrillation Using Apple Watch: A Randomized Controlled Trial. Journal of the American College of Cardiology.
  2. American College of Cardiology, 2026. EQUAL: Smartwatch Monitoring Improves AFib Detection. ACC Journal Scan.
  3. TCTMD, 2026. Smartwatch Increases AF Diagnosis in Older, High-risk Patients: EQUAL. TCTMD.
Hydra Editorial

Hydra's editorial team. We write from primary research and cite every study we rely on, with its year and journal. We quantify claims wherever the evidence allows and state plainly where it does not: where a finding rests on a small or single trial, we say so in the text rather than in a footnote.