Vol. 52 | No. 2 | July-December 2024 Back

Open Access

Accuracy of the Apple Watch in Detecting Atrial Fibrillation Among Patients Undergoing 24-Hour Holter Monitoring: A Prospective, Pragmatic Study

Abstract

BACKGROUND: As smartwatches with atrial fibrillation detection features gain popularity, it is important to assess the accuracy of these devices to guide decision-making.

OBJECTIVES: Our study aimed to assess the sensitivity and specificity of the irregular rhythm notification and the electrocardiogram (ECG)–based detection features of a commonly used smart wearable device (Apple Watch) in detecting atrial fibrillation.

METHODS: This was a prospective, pragmatic study conducted in Perpetual Succour Hospital–Cebu Heart Institute from August 2023 to January 2024. To assess the irregular rhythm notification feature, participants were asked to wear an Apple Watch alongside a 24-hour Holter monitor to verify notifications. For the ECG-based detection feature, participants had to tap the crown of the Apple Watch for 30 seconds to get a single-lead ECG similar to a lead I ECG tracing. They were instructed to get manual ECGs hourly, or more often while awake. Irregular rhythm notifications and ECG readings were then compared with that of the 24-hour Holter monitor. Sensitivity and specificity were then computed.

RESULTS: A total of 140 participants consented to join after full study disclosure. The irregular rhythm notification feature of the Apple Watch exhibited a low sensitivity of 21.4% but achieved a high specificity of 100% in detecting atrial fibrillation. Meanwhile, the ECG-based detection feature, analyzed from 1295 manually taken ECGs with interpretable sinus rhythm or atrial fibrillation, demonstrated a high level of agreement with the Holter monitor, with a sensitivity of 100% and a specificity of 99.1%.

CONCLUSION: The low sensitivity of the irregular rhythm notification feature of the Apple Watch in detecting atrial fibrillation cautions against relying on it as a primary screening tool. However, the high concordance of manually taken Apple Watch ECGs positions the device as a robust tool for detecting atrial fibrillation through manual ECG detection.

KEYWORDS: Apple Watch, atrial fibrillation, smartwatches

  1. Patel NJ, Atti V, Mitrani RD, Viles-Gonzalez JF, Goldberger JJ. Global rising trends of atrial fibrillation: a major public health concern. Heart 2018;104(24):1989–1990. doi:10.1136/heartjnl-2018-313350.
  2. Raja JM, Elsakr C, Roman S, et al. Apple Watch, wearables, and heart rhythm: where do we stand? Ann Transl Med 2019;7(17):417. doi:10.21037/atm.2019.06.79.
  3. Marini C, de Santis F, Sacco S, et al. Contribution of atrial fibrillation to incidence and outcome of ischemic stroke: results from a population-based study. Stroke 2005;36:1115–1119. 10.1161/01.STR.0000166053.83476.4a.
  4. Yang TY, Huang L, Malwade S, Hsu CY, Chen YC. Diagnostic accuracy of ambulatory devices in detecting atrial fibrillation: systematic review and meta-analysis. JMIR Mhealth Uhealth 2021;9(4):e26167. doi:10.2196/26167.
  5. Odutayo A, Wong CX, Hsiao AJ, Hopewell S, Altman DG, Emdin CA. Atrial fibrillation and risks of cardiovascular disease, renal disease, and death: systematic review and meta-analysis. BMJ 2016;354:i4482. doi:10.1136/bmj.i4482.
  6. Kirchhof P, Benussi S, Kotecha D, et al, ESC Scientific Document Group 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J 2016;37(38):2893–2962. doi:10.1093/eurheartj/ehw210.
  7. Isakadze N, Martin SS. How useful is the smartwatch ECG? [published online October 31, 2019]. Trends Cardiovasc Med 2020;30(7):442–448. doi:10.1016/j.tcm.2019.10.010.
  8. Apple Inc. Using Apple Watch for arrhythmia detection. December 2020. https://Apple ECG.apple.com/healthcare/site/docs/Apple_Watch_Arrhythmia_Detection.pdf. Accessed July 1, 2023.
  9. Turakhia MP, Desai M, Hedlin H, et al. Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: the Apple Heart Study [published online September 8, 2018]. Am Heart J 2019;207:66–75. doi:10.1016/j.ahj.2018.09.002.
  10. Perez MV, Mahaffey KW, Hedlin H, et al; Apple Heart Study Investigators. Large-scale assessment of a smartwatch to identify atrial fibrillation. N Engl J Med 2019;381:1909–1917. doi:10.1056/NEJMoa1901183.
  11. Seshadri DR, Bittel B, Browsky D, et al. Accuracy of Apple Watch for detection of atrial fibrillation [published online February 24, 2020]. Circulation 2020;141(8):702–703. doi:10.1161/CIRCULATIONAHA.119.044126.
  12. Inui T, Kohno H, Kawasaki Y, et al. Use of a smart watch for early detection of paroxysmal atrial fibrillation: validation study. JMIR Cardiol 2020;4(1):e14857. doi:10.2196/14857.
  13. Wasserlauf J, You C, Patel R, Valys A, Albert D, Passman R. Smartwatch performance for the detection and quantification of atrial fibrillation. Circ Arrhythm Electrophysiol 2019;12(6):e006834. doi:10.1161/CIRCEP.118.006834.
  14. Apple Inc. Taking an ECG with the ECG app on Apple Watch Series 4. November 18, 2019. https://support.apple.com/en-us/HT208955. Accessed July 1, 2023.

Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, which permits use, share — copy and redistribute the material in any medium or format, adapt — remix, transform, and build upon the material, as long as you give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not use the material for commercial purposes. If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original. You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/4.0/.