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Triage tests for identifying atrial fibrillation in primary care: a diagnostic accuracy study comparing single-lead ECG and modified BP monitors
  1. Karen Kearley1,
  2. Mary Selwood1,
  3. Ann Van den Bruel1,
  4. Matthew Thompson1,2,
  5. David Mant1,
  6. FD Richard Hobbs1,
  7. David Fitzmaurice3,
  8. Carl Heneghan1
  1. 1Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
  2. 2Department of Family Medicine, University of Washington, Seattle, Washington, USA
  3. 3Primary Care Clinical Sciences, University of Birmingham, Birmingham, UK
  1. Correspondence to Dr Matthew Thompson; mjt{at}uw.edu

Abstract

Objective New electronic devices offer an opportunity within routine primary care settings for improving the detection of atrial fibrillation (AF), which is a common cardiac arrhythmia and a modifiable risk factor for stroke. We aimed to assess the performance of a modified blood pressure (BP) monitor and two single-lead ECG devices, as diagnostic triage tests for the detection of AF.

Setting 6 General Practices in the UK.

Participants 1000 ambulatory patients aged 75 years and over.

Primary and secondary outcome measures Comparative diagnostic accuracy of modified BP monitor and single-lead ECG devices, compared to reference standard of 12-lead ECG, independently interpreted by cardiologists.

Results A total of 79 participants (7.9%) had AF diagnosed by 12-lead ECG. All three devices had a high sensitivity (93.9–98.7%) and are useful for ruling out AF. WatchBP is a better triage test than Omron autoanalysis because it is more specific—89.7% (95% CI 87.5% to 91.6%) compared to 78.3% (95% CI 73.0% to 82.9%), respectively. This would translate into a lower follow-on ECG rate of 17% to rule in/rule out AF compared to 29.7% with the Omron text message in the study population. The overall specificity of single-lead ECGs analysed by a cardiologist was 94.6% for Omron and 90.1% for Merlin.

Conclusions WatchBP performs better as a triage test for identifying AF in primary care than the single-lead ECG monitors as it does not require expertise for interpretation and its diagnostic performance is comparable to single-lead ECG analysis by cardiologists. It could be used opportunistically to screen elderly patients for undiagnosed AF at regular intervals and/or during BP measurement.

  • Primary Care
  • Stroke Medicine

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/3.0/

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