Background Detection of atrial fibrillation (AF) in patients who had ischaemic stroke and transient ischaemic attack (IS/TIA) is recommended. We aimed to compare external loop recording (ELR) against simultaneous continuous ECG recording for AF detection in patients who had acute IS/TIA and determine sensitivity, specificity and positive predictive value of AF detection using ELR. We hypothesised ELR to detect 15% fewer patients with AF than continuous ECG recording.
Methods In this prospective cohort study, we included 1412 patients who had acute IS/TIA without prior AF. Monitoring was 48 hours. Primary outcome was AF >30 s. Cardiologist verified AF in continuous ECG was gold standard.
Results In continuous ECG, 38 (2.7%) patients had AF. ELR automatically categorised 219/1412 patients (15.5%) with AF, including 32/38 (85%) patients with AF in continuous ECG. After cardiologist adjudication of ELR recordings, AF was diagnosed in 57/219 patients, of which 32 (56%) had AF in continuous ECG. For adjudicated AF detection by ELR, sensitivity was 84%, 95% CI (69% to 94%), specificity was 98%, 95% CI (97% to 99%) and positive predictive value was 56%, 95% CI (42% to 69%).
Conclusion Automatic AF detection with ELR results in an AF diagnosis in more than five patients without AF for each patient with AF as verified in continuous ECG. For adjudicated AF detection by ELR, sensitivity was confirmed to 84% and specificity 98%. Automatic ELR as investigated in this study may be considered to rule out AF, but it is not suitable as a single monitoring device for AF screening in patients early after stroke.
Trial registration number NCT02155907.
- atrial fibrillation
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Contributors MHS contributed in literature search, fund applications and obtaining permits, figures, study design, data collection, data analysis, data interpretation and writing. JCN contributed in literature search, figures, study design, data analysis, data interpretation, writing and guidance on cardiological aspects. OM contributed in figures, study design, data interpretation, writing and guidance on cardiological aspects. DD contributed in study design, writing and guidance on neurologic aspects. BFS contributed in data collection, writing and guidance on neurologic aspects.
Funding This work was supported by Health Research Fund of Central Denmark Region (1-31-72-15-14), Danish Heart Foundation (14-R97-A5075-22884/17-R115-A7606-22069) and Aase and Ejnar Danielsen Foundation (10-001847). Novo Nordisk Foundation (NNF16OC0018658) and an institutional unrestricted grant from Abbott, Denmark, supported JCN.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Not required.