Atrial fibrillation (AF) stands as a prevalent cardiac arrhythmia and a significant, modifiable risk factor for stroke. Early and accurate detection of AF in primary care settings is crucial for timely intervention and stroke prevention. Recent advancements in electronic devices present a valuable opportunity to enhance AF detection within routine primary care. This study rigorously evaluated the diagnostic performance of a modified blood pressure (BP) monitor and two single-lead ECG devices as initial triage tests for identifying AF in an ambulatory primary care population.
Conducted across six General Practices in the UK, the study involved 1000 participants aged 75 years and over. The core objective was to compare the diagnostic accuracy of the WatchBP monitor and single-lead ECG devices (Omron and Merlin) against the gold standard 12-lead ECG, interpreted by cardiologists. The study focused on sensitivity and specificity as key metrics for evaluating each device’s effectiveness in Af Diagnosis In Primary Care.
The findings revealed that 7.9% of participants were diagnosed with AF by 12-lead ECG. Notably, all three devices demonstrated high sensitivity (93.9-98.7%), proving their utility in effectively ruling out AF. However, significant differences emerged in specificity. The WatchBP monitor exhibited superior specificity at 89.7% (95% CI 87.5% to 91.6%) compared to the Omron autoanalysis at 78.3% (95% CI 73.0% to 82.9%). This enhanced specificity of WatchBP translates to a potentially lower rate of follow-on ECGs (17%) needed to definitively rule in or rule out AF, in contrast to the 29.7% rate associated with the Omron device in the study population. The overall specificity of single-lead ECGs when analyzed by a cardiologist was 94.6% for Omron and 90.1% for Merlin, indicating the impact of expert interpretation on single-lead ECG accuracy.
In conclusion, the WatchBP monitor emerges as a more effective triage tool for AF diagnosis in primary care compared to single-lead ECG monitors. Its key advantage lies in comparable diagnostic performance to cardiologist-analyzed single-lead ECGs without requiring specialized expertise for interpretation. This ease of use and high specificity positions WatchBP as a valuable asset for opportunistic screening of elderly patients for undiagnosed AF during routine BP measurements, contributing to improved and proactive AF diagnosis in primary care settings.
