Reference: J Am Coll Cardiol 2026 Jan 22 early online
Practice Point: Smartwatch heart monitoring may increase detection of atrial fibrillation, capturing a real-world opportunity for stroke risk reduction.
EBM Pearl: When earlier treatment meaningfully reduces risk, early detection isn’t overdiagnosis, it’s an open door to improved outcomes.
Let’s start with the basics. Atrial fibrillation (AF) is a serious arrhythmia primarily because of its association with ischemic stroke. The CHA2DS2-VASc score is used in patients with AF to assess risk of stroke, and initiating anticoagulation is typically recommended when the estimated annual risk reaches ≥ 2%, represented by a score of ≥ 2 in men and ≥ 3 in women. New detection methods, such as smartwatches, have gained popularity for detecting AF, but it’s unclear how clinically useful they are.
The EQUAL trial enrolled 437 patients ≥ 65 years old with elevated stroke risk (CHA2DS2-VASc score ≥ 2 in men and ≥ 3 in women) from two outpatient cardiology clinics in the Netherlands. Overall, the median CHA2DS2-VASc score was 3. Participants were randomized to smartwatch-based heart monitoring or usual care over a 6-month period. Patients in the smartwatch group were instructed to wear the device (an Apple Watch series 5 or 8) for at least 12 hours daily and could record a 30-second single-lead electrocardiogram (ECG) either when symptomatic or in response to an irregular rhythm notification. Usual care was left to clinician discretion and included options such as 12-lead ECGs, Holter monitoring, inpatient telemetry, or handheld mobile ECG devices.
The smartwatch strategy led to significantly higher detection of new-onset AF compared with usual care (9.6% vs. 2.3%, p = 0.001). Notably, 57% of AF episodes detected in the smartwatch group were asymptomatic and 90% were paroxysmal compared to 0% and 80%, respectively, in the usual care group. AF is generally considered a surrogate outcome, as it’s a marker of a biological function that may not always be clinically meaningful to the patient and impact their daily life. Importantly, the trial was not powered to detect differences in the key clinical outcome of stroke. Rates of major adverse cardiovascular events were low in both groups (0.9%).
This raises the issue of overdiagnosis, in which screening identifies a condition that would never have caused symptoms or harm, but leads to a treatment without a real chance of benefit. A classic example is indolent prostate cancer detected through screening that would never have become clinically significant yet exposes patients to treatments with meaningful harms. AF is different. Stroke risk in AF, particularly in patients with higher CHA2DS2-VASc scores, is an annual risk, not a cumulative risk that grows higher in time. That means there is an ongoing opportunity for benefit from treatment of AF, even as we acknowledge the ongoing risk of potential harms from treatment. So in this case, earlier detection of AF (followed by earlier treatment) likely translates into a meaningful reduction in stroke risk. However, it’s worth noting that awareness of an arrhythmia can provoke anxiety and lead to behaviors such as exercise avoidance and compulsive self-monitoring, so touching base with patients about these factors is important.
Wearable health monitoring is no longer a futuristic concept—it’s already in our clinics and on our patients’ wrists. This study makes it pretty clear that these tools increase detection of AF, supporting the use of this type of technology for screening in high-risk patients. As adoption accelerates, the goal of detecting arrhythmias sooner can be achievable, and can likely help improve outcomes in ways that truly matter to patients.
For more information, see the topic Atrial Fibrillation Screening in DynaMed.
DynaMed EBM Focus Editorial Team
This EBM Focus was written by McKenzie Ferguson, PharmD, BCPS, Senior Clinical Writer at DynaMed. Edited by Katharine DeGeorge, MD, MS, Executive Editor at DynaMed and Associate Professor of Family Medicine at the University of Virginia; Alan Ehrlich, MD, FAAFP, Executive Editor at DynaMed and Associate Professor in Family Medicine at the University of Massachusetts Medical School; Rich Lamkin, MPH, MPAS, PA-C, Senior Clinical Writer at DynaMed; Claire Symanski, PhD, Medical Editor and Team Lead for ENT at DynaMed; Michael Butler, PhD, Medical Writer at DynaMed; Matthew Lavoie, BA, Senior Medical Copyeditor at DynaMed; Hannah Ekeh, MA, Senior Associate Editor II at DynaMed; and Jennifer Wallace, BA, Senior Associate Editor at DynaMed.