Spot-check measurement using pulse deriving smartwatch to detect atrial fibrillation

Validation study of a pulse-deriving wrist band using spot-check measurements to detect atrial fibrillation

Introduction: Atrial Fibrillation (AF) screening can nowadays be carried out using mobile and wearable single-lead ECG technologies. A novel technology, photoplethysmography (PPG), is an alternative technique to detect AF by measuring blood-pulse waves optically.

Objective: In this validation study, the diagnostic performance of two wearable technologies was evaluated. Expert review of the single-lead ECG traces was used as reference.

Methods: An observational prospective cohort study was set up in which subjects were randomly invited to participate. Inclusion criteria were older than 18 years and no cardiac device that could influence the heart rhythm. Demographic and medical history data was collected. Subjects were instructed to perform three consecutive measurements using a wearable single-lead ECG (Kardia band, Alivecor) and a wearable PPG wrist band (Wavelet health band, Wavelet) simultaneously. Analysis was performed on measurement level as well as on participant level. The single-lead ECG traces were revised by two independent blinded reviewers. Inconsistencies were evaluated by a third reviewer. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were determined to validate the accuracy of both wearable technologies.

Results: A total of 60 subjects were included with a mean age of 70±17 and 32% of the study population was male. AF was identified in 6 (10%) of the subjects, of which 4 were previously undiagnosed. The Pearson correlation of heart rate between the two technologies was 0.9 (P < 0.001). The diagnostic performance (sens/spec/NPV/PPV) after bad-quality exclusion was (72/98/97/81%) for the ECG wrist band and (79/98/98/85) for the PPG wrist band. On participant level, the diagnostic performance increased towards (83/98/98/83%) for ECG and (100/98/100/83%) for PPG. No inconsistencies have been observed between both reviewers.

Conclusion: This feasibility study demonstrates the opportunity to use wearable technologies for the detection and screening of atrial fibrillation. The optical PPG technology showed comparable results to the current state-of-the-art single lead ECG devices. Despite the need for further research, it opens the perspective that these spot-checks could hold the potential towards continuous monitoring.