Smart watches for heart rate assessment in atrial arrhythmias

Int J Cardiol. 2018 Sep 1;266:124-127. doi: 10.1016/j.ijcard.2018.02.073.


Background: Despite studies demonstrating the accuracy of smart watches (SW) and wearable heart rate (HR) monitors in sinus rhythm, no data exists regarding their utility in arrhythmias.

Methods: 102 hospitalized patients were evaluated at rest using continuous electrocardiogram (ECG) monitoring with concomitant SW-HR (FitBit, FB, Apple Watch, AW) for 30 min.

Results: Across all devices, 38,616 HR values were recorded. Sinus rhythm cohort demonstrated strong agreement for both devices with a low bias (FB & AW Bias = 1 beat). In atrial arrhythmias, AW demonstrated a stronger correlation than FB (AW rs = 0.83, FB rs = 0.56, both p < 0.01) with a lower bias (Bias AW = -5 beats, FB = -18 beats). Atrial flutter demonstrated strongest agreement in both devices with a mean bias <1 beat. However, in AF, there was significant HR underestimation (Bias FB = -28 beats, AW-8 beats) with wide limits of agreement. Despite HR underestimation in AF, when SW recorded HR ≥ 100 in arrhythmias, 98% of values were within ±10-beats of ECG-HR.

Conclusions: SW demonstrate strong agreement for HR estimation in sinus rhythm and atrial flutter but underestimates HR in AF. Tachycardic episodes recorded at rest on a SW may be suggestive of an underlying atrial tachyarrhythmia and warrant further clinical evaluation.

Clinical trial registration: Australian New Zealand Clinical Trials Registry ( ACTRN: 12616001374459.

Keywords: Accuracy; Arrhythmias; Atrial fibrillation; Heart rate; Smart watch.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Atrial Fibrillation / diagnosis*
  • Atrial Fibrillation / physiopathology*
  • Electrocardiography, Ambulatory / instrumentation
  • Electrocardiography, Ambulatory / methods*
  • Female
  • Fitness Trackers*
  • Heart Rate / physiology*
  • Humans
  • Male
  • Middle Aged
  • Prospective Studies
  • Wearable Electronic Devices*