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Smartwatches do a good job of identifying atrial fibrillation, according to a meta-analysis in JACC. The authors considered data from 26 studies that included 17,349 participants and found that smartwatches detect atrial fibrillation with high accuracy. Overall sensitivity was 94.8%, and specificity was 96.4%. The accuracy of the results varied when comparing each individual device, however. According to the authors, Amazfit (99% sensitivity; 99% specificity) and Samsung (97% sensitivity; 96% specificity) models performed at the higher end of accuracy assessments, while Apple Watch (94% sensitivity; 97% specificity) devices also showed strong but slightly lower values. For comparison, Fitbit had the lowest performance (66% sensitivity; 79% specificity). Meta-regression suggested that differences between brands were largely explained by study sample size rather than real-world device performance. For some devices, only 1 or 2 studies met criteria for the analysis.
Worth a follow-up: Although smartwatches can reliably identify atrial fibrillation, they are generally used for screening to encourage users to seek clinical testing and verification. Extrapolated estimates show 3.3 million people in the United States likely had atrial fibrillation as of 2020, so the opportunity to identify the condition is significant.