Validation of Smartwatches Integrated With Photoplethysmography for Continuous Evaluation of Atrial Fibrillation...

Smartwatches integrated with photoplethysmography (PPG) can effectively identify the occurrence of atrial fibrillation (AF). However, the accuracy of their continuous monitoring of AF burden is still unclear.

This study sought to verify the effectiveness of a smartwatch integrated with the PPG algorithm in continuously monitoring AF burden.

This prospective study included patients diagnosed with AF at Beijing Anzhen Hospital between January and December 2024. Each participant continuously wore a smartwatch integrated with the PPG algorithm on the day prior to radiofrequency catheter ablation, together with patch-based electrocardiography (P-ECG) as the reference to validate algorithm performance for estimation of AF burden. The watch-based PPG data were segmented into 30-second intervals and verified with the data from P-ECG to analyze its accuracy, sensitivity, and specificity.

The study recruited 728 participants, with a mean age of 62.0 ± 10.5 years, of whom 412 (56.6%) had paroxysmal AF. The average monitoring time for each participant was 20.4 ± 4.5 hours. The overall validity rate for P-ECG was 96.2%, while the overall validity rate for watch-based PPG was 62.5%. After segmentation, a total of 1,440,826 PPG records were generated. At the interval level, sensitivity was 98.70% (95% CI: 98.66%-98.73%) and specificity was 99.56% (95% CI: 99.54%-99.57%). At the individual level, sensitivity was 91.73% (95% CI: 88.89%-94.15%) and specificity was 96.96% (95% CI: 95.09%-98.59%). The Bland-Altman analysis showed excellent agreement between the AF burden estimates from PPG and electrocardiography (ECG), with a mean difference of -1.34% and 95% limits of agreement ranging from -6.45% to 3.77%. A strong correlation (r = 0.999) was observed between PPG-based and ECG-measured AF burden (NCT05333380).

Smartwatches integrated with the PPG algorithm offer a practical and noninvasive approach for continuous AF burden monitoring. The results suggest that PPG can be an effective approach for long-term AF management, providing an accessible alternative to traditional ECG monitoring.