Placement of a wrist-worn PPG monitor three fingers above the wrist significantly improved accuracy compared to one finger above (mean difference in MAPE: -11.4%, P<0.001).
Observational (n=50)
Do technical interventions and optimal sensor placement improve the accuracy of wrist-worn PPG heart rate monitors in patients with cardiac disease?
Wrist-worn PPG heart rate monitors require optimal placement higher on the wrist for accuracy, and baseline accuracy assessment is necessary as only two-thirds of cardiac rehabilitation patients are suitable for such monitoring.
Mean Difference: -11.4
p-value: p=< 0.001
Abstract Introduction Sensor placement, activity type influencing wrist movements, and individual characteristics impact accuracy of wrist-worn photoplethysmography (PPG)-based heart rate (HR) monitors. This study investigated technical interventions to optimize PPG accuracy in patients with cardiac disease. Methods and results The Fitbit Inspire 2 PPG monitor was evaluated across three cohorts, using a Polar H10 chest strap as reference: (ⅰ) 10 healthy volunteers performed wrist movements with the monitor placed one or three fingers above the wrist to identify optimal placement; (ⅱ) 10 volunteers engaged in sport activities (walking, running, cycling, rowing); (ⅲ) 30 cardiac rehabilitation patients were monitored during exercise to assess baseline accuracy. Patients with low accuracy mean absolute percentage error (MAPE) 10% for 70% of training time underwent technical interventions (sensor cleaning, forearm shaving, position fixation, and/or relocation to the volar wrist). Placement three vs. one fingers above the wrist was significantly more accurate (mean difference in MAPE: −11.4%, P 0.001). Walking showed the highest accuracy (MAPE = 3.8%), followed by cycling (MAPE = 6.9%) and running (MAPE = 8.5%), while rowing had the lowest accuracy (MAPE = 13.4%, P 0.001). Among CR patients, 66.7% achieved high baseline accuracy. Technical interventions improved accuracy in 50.0% of those with low baseline accuracy, but no significant predictors of optimization success were identified. Conclusion Accurate PPG-based monitoring requires a sensor placed higher on the wrist. Nevertheless, only two-thirds of patients are suitable for such monitoring, with improvement by technical adaptations possible (but impractical) in the others. Therefore, assessing baseline accuracy is a prerequisite before relying on these devices for activity guidance.
Vermunicht et al. (Tue,) conducted a observational in Cardiac disease (n=50). Placement of PPG monitor three fingers above the wrist vs. Placement one finger above the wrist was evaluated on Mean absolute percentage error (MAPE) (MD -11.4%, p=< 0.001). Placement of a wrist-worn PPG monitor three fingers above the wrist significantly improved accuracy compared to one finger above (mean difference in MAPE: -11.4%, P<0.001).