Accuracy of the Apple Watch for Detection of AF: A Multi-Center Experience.

BACKGROUND: The Apple Watch (AW) Irregular Rhythm Notification (IRN) feature uses photoplethysmography to identify prolonged episodes of irregular rhythm suggestive of atrial fibrillation (AF). IRN is FDA cleared for those with no previous history of AF, however, these devices are increasingly being used for AF management.

OBJECTIVE: To determine the accuracy of the IRN in subjects with a previous diagnosis of non-permanent AF.

METHODS: Subjects with a history of non-permanent AF and either an insertable cardiac monitor (ICM) or cardiac implanted electronic device (CIED) with < 5% ventricular pacing were fitted with an AW Series 5 for 6 months. AF episodes were compared between the ICM/CIED and IRN. The primary endpoints were sensitivity, specificity, PPV, and NPV of the IRN by subject for AF ≥ 1 hour. Secondary endpoints were sensitivity and PPV by AF episode ≥ 1 hour. Analysis was limited to a maximum of 10 ICM/CIED episodes per subject and included only those AF episodes occurring during active AW use confirmed by activity data.

RESULTS: Thirty participants, mean age was 65.4y ± 12.2y, 40% female, were enrolled. There were 10 ICMs and 20 CIEDs. 11 subjects had AF on ICM/CIED while the AW was worn, of whom 8 were detected by IRN. There were no false positive IRN detections by subject ("by subject" 72% sensitivity, 100% specificity, 100% PPV, and 90% NPV). 5 subjects had AF only when the AW was not worn. There were a total of 70 AF episodes on ICM/CIED, 35 of which occurred while the AW was being worn. Of these, 21 were detected by IRN with 1 false positive ("by episode" sensitivity = 60.0%, PPV = 95.5%).

CONCLUSION: In a population with known AF, the AW IRN had a low rate of false positive detections and high specificity. Sensitivity for detection by subject and by AF episode was lower. The current IRN algorithm appears accurate for AF screening as currently cleared, but increased sensitivity and wear times would be necessary for disease management. This article is protected by copyright. All rights reserved.