Triage tests for identifying atrial fibrillation in primary care: a diagnostic accuracy study comparing single-lead ECG and modified BP monitors. Issue 5 (2nd May 2014)

• Record Type: Journal Article
• Authors: Kearley, Karen; Selwood, Mary; Van den Bruel, Ann; Thompson, Matthew; Mant, David; Hobbs, FD Richard; Fitzmaurice, David; Heneghan, Carl
• Is Part Of: BMJ open. Volume 4:Issue 5(2014)
• Publication Date: 2014-05-02
• Subjects: Primary Care -- Stroke Medicine; Medicine -- Research -- Periodicals; 610.72
• DOI: 10.1136/bmjopen-2013-004565
• Languages: English
• ISSNs: 2044-6055

Abstract

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.