Insertable Cardiac Monitoring Results in Higher Rates of Atrial Fibrillation Diagnosis and Oral Anticoagulation Prescription after Ischaemic Stroke.

BACKGROUND AND AIMS: After an ischaemic stroke, atrial fibrillation (AF) detection allows for improved secondary prevention strategies. This study aimed to compare AF detection and oral anticoagulant (OAC) initiation in patients with an insertable cardiac monitor (ICM) versus external cardiac monitor (ECM) after ischaemic stroke.

METHODS: Medicare Fee-for-Service (FFS) insurance claims and Abbott Labs device registration data were used to identify patients hospitalized with an ischaemic stroke in 2017-2019 who received an ICM or ECM within three months. Patients with continuous Medicare FFS insurance and prescription drug enrolment in the prior year were included. Patients with prior AF, atrial flutter, cardiac devices, or OAC were excluded. ICM and ECM patients were propensity score matched 1:4 on demographics, comorbidities, and stroke hospitalization characteristics. The outcomes of interest were AF detection and OAC initiation evaluated with Kaplan-Meier and Cox proportional hazard regression analyses.

RESULTS: A total of 5,702 Medicare beneficiaries (ICM, n=444; ECM, n=5,258) met inclusion criteria. The matched cohort consisted of 2,210 Medicare beneficiaries (ICM, n=442; ECM, n=1,768) with 53% female, mean age 75 years, and mean CHA₂DS₂-VASc score 4.6 (1.6). ICM use was associated with a higher probability of AF detection (hazard ratio (HR) 2.88, 95% confidence interval (CI) [2.31, 3.59]) and OAC initiation (HR 2.91, CI [2.28, 3.72]) compared to patients monitored only with ECM.

CONCLUSION: Patients with an ischaemic stroke monitored with an ICM were almost 3 times more likely to be diagnosed with AF and to be prescribed OAC compared to patients who received ECM only.