Clinical implications of delayed insertion of implantable loop recorder: Is it still beneficial when inserted years after a stroke?

BACKGROUND

The efficacy of an implantable loop recorder (ILR) has been proven in detecting atrial fibrillation (AF) in embolic stroke of undetermined source (ESUS) patients. However, when patients should get ILR remains uncertain.

OBJECTIVE

We investigated whether ILR insertion timing was associated with the incidence of AF detection and clinical outcomes.

METHODS

We identified ESUS patients receiving an ILR insertion between July 2016 and October 2021 using National Health Insurance claims data. Patients were classified based on the ILR insertion timing. The early implant was defined as ≤2 months from stroke, and the late implant was defined as >1 year.

RESULTS

Among 1509 patients, 386 (25.6%) were classified into early and 772 (51.2%) into late implant groups. Patients in the early group were younger and had a lower prevalence of hypertension, diabetes, and heart failure than those in the late group. The incidence of AF was higher in the early group than in the late group (HR 1.49, 95% CI 1.21-1.85, p < 0.001). However, clinical outcomes, including recurrent stroke, all-cause mortality, and major bleeding, were not different between the groups. The risk of recurrent stroke and major bleeding did not increase following AF detection, although the mortality risk did.

CONCLUSION

In this nationwide cohort study, the incidence of AF detection was higher in ESUS patients when ILR was inserted within 2 months than after a year from stroke. From the perspective of AF, inserting an ILR earlier is superior; however, delayed insertion may still offer potential advantages.