Intended for healthcare professionals


Accuracy of diagnosing atrial fibrillation on electrocardiogram by primary care practitioners and interpretative diagnostic software: analysis of data from screening for atrial fibrillation in the elderly (SAFE) trial

BMJ 2007; 335 doi: (Published 23 August 2007) Cite this as: BMJ 2007;335:380
  1. Jonathan Mant, reader1,
  2. David A Fitzmaurice, professor of primary care1,
  3. F D Richard Hobbs, professor and head of department1,
  4. Sue Jowett, research fellow2,
  5. Ellen T Murray, research fellow1,
  6. Roger Holder, head of statistics1,
  7. Michael Davies, consultant cardiologist3,
  8. Gregory Y H Lip, professor of cardiovascular medicine4
  1. 1Department of Primary Care and General Practice, University of Birmingham, Birmingham B15 2TT
  2. 2Health Economics Facility, Health Services Management Centre, University of Birmingham, Birmingham B15 2RT
  3. 3Department of Cardiology, Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH
  4. 4University Department of Medicine, City Hospital, Birmingham B18 7QH
  1. Correspondence to: D A Fitzmaurice d.a.fitzmaurice{at}
  • Accepted 21 May 2007


Objective To assess the accuracy of general practitioners, practice nurses, and interpretative software in the use of different types of electrocardiogram to diagnose atrial fibrillation.

Design Prospective comparison with reference standard of assessment of electrocardiograms by two independent specialists.

Setting 49 general practices in central England.

Participants 2595 patients aged 65 or over screened for atrial fibrillation as part of the screening for atrial fibrillation in the elderly (SAFE) study; 49 general practitioners and 49 practice nurses.

Interventions All electrocardiograms were read with the Biolog interpretative software, and a random sample of 12 lead, limb lead, and single lead thoracic placement electrocardiograms were assessed by general practitioners and practice nurses independently of each other and of the Biolog assessment.

Main outcome measures Sensitivity, specificity, and positive and negative predictive values.

Results General practitioners detected 79 out of 99 cases of atrial fibrillation on a 12 lead electrocardiogram (sensitivity 80%, 95% confidence interval 71% to 87%) and misinterpreted 114 out of 1355 cases of sinus rhythm as atrial fibrillation (specificity 92%, 90% to 93%). Practice nurses detected a similar proportion of cases of atrial fibrillation (sensitivity 77%, 67% to 85%), but had a lower specificity (85%, 83% to 87%). The interpretative software was significantly more accurate, with a specificity of 99%, but missed 36 of 215 cases of atrial fibrillation (sensitivity 83%). Combining general practitioners' interpretation with the interpretative software led to a sensitivity of 92% and a specificity of 91%. Use of limb lead or single lead thoracic placement electrocardiograms resulted in some loss of specificity.

Conclusions Many primary care professionals cannot accurately detect atrial fibrillation on an electrocardiogram, and interpretative software is not sufficiently accurate to circumvent this problem, even when combined with interpretation by a general practitioner. Diagnosis of atrial fibrillation in the community needs to factor in the reading of electrocardiograms by appropriately trained people.


  • We are grateful for the support of the practices that participated in the SAFE study and for the support provided by the Midlands Research Practices Consortium.

  • Contributors: JM, DAF, FDRH, ETM, MD, and GYHL were involved in the design of this sub-study as investigators in the SAFE study, which is led by DAF and FDRH. SJ, JM, and RH did this analysis. ETM and SJ managed the project. MD and GYHL read the electrocardiograms. JM was responsible for writing the drafts of this paper, to which all the authors contributed. JM is the guarantor.

  • Funding: The work was funded by the Health Technology Assessment Programme. The authors are independent from the funders of the research. The views expressed in this publication are those of the authors and not necessarily those of the funders or the Department of Health.

  • Competing interests: None declared.

  • Ethical approval: West Midlands Multi-centre Research Ethics Committee approved the SAFE study.

    Provenance and peer review: Non-commissioned; externally peer reviewed.

  • Accepted 21 May 2007
View Full Text