Smartwatch Atrial Fibrillation Detection: Systematic Review Shows Varied Accuracy
A new systematic review published today, November 8, 2025, indicates that the accuracy of atrial fibrillation (AFib) detection varies significantly across different smartwatch models.
The review, which analyzed existing studies, found that while smartwatches show promise in identifying irregular heart rhythms indicative of AFib, sensitivity – the ability to correctly identify those *with* the condition – is prioritized over specificity, meaning some healthy individuals may receive false positive results. This is a crucial consideration, as undetected AFib can significantly increase the risk of stroke and other serious health complications.
Researchers found that the performance of these devices is highly dependent on the specific model and the methodology used in individual studies, with varying numbers of test subjects per device. The study highlights the importance of understanding that these devices are screening tools, not definitive diagnostic replacements, and further evaluation by a medical professional is always necessary following a positive result. For more information on understanding heart health, resources are available from the American Heart Association.
Because the review is currently in the preprint stage, it has not yet undergone full peer review, and the rapidly evolving technology in this field means results may change as new devices enter the market. Understanding the nuances of wearable technology and heart health is becoming increasingly important as more people utilize these devices for health monitoring; you can learn more about wearable health technology here.
Officials recommend consulting with a healthcare provider for accurate diagnosis and treatment of atrial fibrillation, regardless of smartwatch findings.
Some background information may be needed for interpretation and classification, along with an explanation of technical terms. In a medical-diagnostic context, sensitivity specifically indicates how many diseases or “abnormalities” are detected, while specificity indicates how many healthy individuals are correctly identified as healthy. As described in our analysis of the Apple Watch’s blood pressure function, these two values are related. Diagnostic procedures can be optimized for higher sensitivity or specificity within certain limits, provided that the procedure is generally suitable. In a screening procedure such as the detection of atrial fibrillation, high sensitivity should be clearly prioritized over high specificity, at least from the individual patient’s perspective. While a false-positive result might lead to wasted waiting time at the doctor’s office and an unnecessary ECG, this is, of course, a far better alternative to the increased risk of mortality associated with undetected atrial fibrillation.
Background information on the study
The study is a systematic review, meaning that Barrera N et al. did not take any measurements themselves, but rather reviewed existing studies and included them in the evaluation (or not). The advantages of such studies are that the number of cumulative participants is very high and the number of different brands/devices tested is greater. At this point, we would like to clearly point out that this review cumulates different, specific model variants from individual manufacturers and that the number of test subjects per specific device varies greatly in some cases. Furthermore, the measurement methods used in the individual studies are not always the same. The study by Barrera N et al. is currently still in the preprint stage and so has not yet been peer-reviewed. Lastly, the research landscape may still change if, for example, new devices come onto the market.
