AF more often detected by implantable vs. external loop recorder after stroke

Introduction and methods

Approximately one-third of all ischemic strokes is caused by atrial fibrillation (AF) or atrial flutter [1]. Guidelines suggest etiologic investigations in patients with recent ischemic stroke, without evidence of AF on ECG and Holter monitoring [2,3]. It has been shown that both external and implantable loop recorders improve detection of AF in patients with a recent ischemic stroke [4-6]. However, a direct comparison of the detection rates of AF with an external loop recorder versus an implantable loop recorder is missing. This randomized clinical trial compared the detection rate of AF with use of an implantable loop recorder for 12 months vs. use of an external loop recorder for 30 days in patients with a recent ischemic stroke and without known AF.

The Post-Embolic Rhythm Detection with Implantable vs External Monitoring (PER DIEM) trial was an investigator-initiated, open-label trial which was conducted at 3 hospitals in Alberta, Canada. A total of 300 patients (median age 64.1 years, 40.3% women, median CHA2DS2VASc score 4) with recent ischemic stroke (≤6 months before randomization) and without known AF were randomized to receive either an external loop recorder for 30 days (n=150) or an implantable loop recorder (n=150). The primary outcome was definite or highly probable new AF, defined as adjudicated new AF lasting >2 minutes within 12 months of randomization. Reported secondary outcomes included a composite endpoint of AF lasting ≥2 minutes or death within 12 months, time to event analysis of new AF, recurrent ischemic stroke, TIA, intracerebral hemorrhage, death and device-related adverse events within 12 months.

Main results

• The primary outcome of definite or highly probably AF within 12 months was observed significantly more often in patients with an implantable loop recorder (25 of 150, 15.3%), than in patients with an external loop recorder (7 of 150, 4.7%) (risk ratio 3.29, 95%CI 1.45-7.42, P=0.003).
• Time to first detected episode of AF was significantly lower in the implantable loop recorder group, compared to the external loop recorder group (adjusted HR 3.36, 95%CI 1.44-7.84, P=0.005, log-rank test P=0.002).
• The composite secondary endpoint of time to first detected episode of AF lasting ≥2 minutes or death within 12 months occurred in 6.7% of patients with an external loop recorder and in 17.3% of patients with an implantable loop recorder (between-group difference, 10.7%, 95%CI 3.4%-17.9%, P=0.007; adjusted HR 2.64, 95%CI 1.27-5.49, P=0.009).
• No significant differences between the two groups were found for the secondary outcomes of recurrent ischemic stroke, TIA, intracerebral hemorrhage and death within 12 months of randomization.
• One device-related serious adverse event was reported in the implantable loop recorder group compared to none in the external loop recorder group. The affected patient with an implantable loop recorder experienced skin erosion overlying the device. The device was removed at 2 months, without further consequences.

Conclusion

References

Find this article online at JAMA.