Abstract 13805: Accuracy of the Apple Watch Electrocardiogram to Detect Atrial Fibrillation in a Real-World Clinical Setting

Abstract

Introduction: The Apple Watch is the first commercially available wearable device with built-in electrocardiogram (ECG) electrodes to perform a one-lead ECG to detect atrial fibrillation (AF). Studies on the accuracy of the one-lead ECG of the Apple Watch (AW ECG) are limited and show inconclusive results. Our aim is to study the accuracy of the AW ECG in a real-world clinical setting. Methods: Patients with AF who were scheduled for electrical cardioversion (ECV) were included in this study. The Apple Watch series 6 was used with WatchOS 7.2 or 7.3. The AW ECG and 12-lead ECG were obtained pre-ECV. Post-ECV the ECGs were only obtained when the ECV resulted in sinus rhythm (SR). In case of an inconclusive measurement or poor recording, the AW ECG was repeated up to three times. All 12-lead ECGs were blindly adjudicated by two physicians. The AW ECG notification was compared to the physicians ‘gold-standard’ interpretation of the 12-lead ECG. Sensitivity and specificity of the AW ECG and Kappa coefficient between AW ECG and 12-lead ECG were calculated. Results: In total, 74 patients were included. Mean age was 67.1 ± 12.3 years, 20.3% were female, 18.9% had a cardiac implantable electronic device and the mean BMI was 28.1 ± 6.0 kg/m 2 . In total, 65 AF and 64 SR AW ECG and 12-lead ECG measurements were obtained. The first measurement with the Apple Watch compared to the 12-lead ECG showed a sensitivity of 93.5% and specificity of 100% (K=0.94). There were 7.0% inconclusive measurements and 17.8% poor recordings. A second measurement in patients with inconclusive or poor recordings resulted in a sensitivity of 94.6%, specificity of 100% (K=0.95) and 3.9% inconclusive measurements and 7.8% poor recordings. A third measurement in patients with two times an inconclusive or poor recording resulted in a sensitivity of 93%, a specificity of 96.5% (K=0.90) and 3.1 % inconclusive measurements and 5.4% poor recordings. Conclusions: The one-lead ECG of the Apple Watch shows a high accuracy for detecting AF in a real-world clinical setting. Repeating the measurement once decreases the total of unclassified recordings, however a third measurement resulted in a lower accuracy and the occurrence of false positive measurements.