Validity of a smartwatch for detecting atrial fibrillation in patients after heart valve surgery: a prospective observational study

Scand Cardiovasc J. 2024 Dec;58(1):2353069. doi: 10.1080/14017431.2024.2353069. Epub 2024 May 25.


Objectives: Atrial fibrillation (AF) is a common early arrhythmia after heart valve surgery that limits physical activity. We aimed to evaluate the criterion validity of the Apple Watch Series 5 single-lead electrocardiogram (ECG) for detecting AF in patients after heart valve surgery.

Design: We enrolled 105 patients from the University Hospital of North Norway, of whom 93 completed the study. All patients underwent single-lead ECG using the smartwatch three times or more daily on the second to third or third to fourth postoperative day. These results were compared with continuous 2-4 days ECG telemetry monitoring and a 12-lead ECG on the third postoperative day.

Results: On comparing the Apple Watch ECGs with the ECG monitoring, the sensitivity and specificity to detect AF were 91% (75, 100) and 96% (91, 99), respectively. The accuracy was 95% (91, 99). On comparing Apple Watch ECG with a 12-lead ECG, the sensitivity was 71% (62, 100) and the specificity was 92% (92, 100).

Conclusion: The Apple smartwatch single-lead ECG has high sensitivity and specificity, and might be a useful tool for detecting AF in patients after heart valve surgery.

Keywords: Smartwatch; atrial fibrillation; heart valve surgery; sensitivity; single-lead ECG; specificity; validity.

Publication types

  • Observational Study
  • Validation Study
  • Comparative Study

MeSH terms

  • Aged
  • Atrial Fibrillation* / diagnosis
  • Atrial Fibrillation* / physiopathology
  • Cardiac Surgical Procedures / adverse effects
  • Electrocardiography
  • Electrocardiography, Ambulatory / instrumentation
  • Female
  • Heart Rate*
  • Heart Valves / physiopathology
  • Heart Valves / surgery
  • Humans
  • Male
  • Middle Aged
  • Mobile Applications
  • Norway
  • Predictive Value of Tests*
  • Prospective Studies
  • Reproducibility of Results
  • Telemetry / instrumentation
  • Time Factors
  • Treatment Outcome
  • Wearable Electronic Devices