Limited Diagnostic Yield of Long-Term Rhythm Monitoring for ED Observation Unit Patients Evaluated for Transient...

Patients evaluated for transient ischemic attack (TIA) in the emergency department observation unit (EDOU) may be discharged with a long-term rhythm monitor to assess for atrial fibrillation (AF) and atrial flutter (AFL). We aimed to assess the diagnostic yield of long-term rhythm monitoring for diagnosing AF and AFL in an EDOU cohort of patients evaluated for TIA.

We conducted an observational cohort study, in which patients ≥18 years old who were evaluated in the EDOU TIA Protocol at an academic tertiary care center from July 1, 2021 to December 1, 2023 were accrued. This analysis included patients who received a long-term rhythm monitor (Zio Patch) at the time of EDOU discharge. Monitor results were reviewed for diagnoses of AF or AFL. Diagnostic yield, defined as the proportion receiving monitoring who had a new diagnosis of AF or AFL, was calculated with an exact 95% confidence interval (95% CI) and used to determine the number needed to test.

Of the 523 EDOU TIA protocol patients, 59.7% (312/523) were female, 29.6% (155/523) were non-White, and the mean age was 65.9 ± 14.9 years. At discharge, 18.4% (96/523) received long-term rhythm monitoring, which identified AF in 5.2% (5/96) and AFL in 1.0% (1/96). However, 3 of these patients already had known AF/AFL. Thus, the yield for diagnosing new AF/AFL was 3.1% (3/96, 95% CI, 0.7%-8.9%), with a number needed to test of 32.

The diagnostic yield of long-term rhythm monitoring for diagnosing AF/AFL among discharged EDOU TIA protocol patients was low, suggesting it may be overprescribed in this population.