Monitoring with an insertable cardiac monitor (ICM) detected significantly more episodes of atrial fibrillation (AF) compared with usual care in patients who had a stroke attributed to large- or small-vessel disease, according to study results published in JAMA.

In this multicenter, randomized, parallel-group clinical trial (STROKE-AF; Identifier: NCT02700945), researchers compared the rate of AF detection with an ICM as opposed to usual care in patients with an index ischemic stroke attributed to as large-artery atherosclerosis (large-vessel disease) or small-vessel occlusion (small-vessel disease). Patients were aged 60 years and older; those who were 50 to 59 years were included if they had documented medical history of at least 1 of the following stroke risk factors: congestive heart failure, hypertension, diabetes, ischemic stroke more than 90 days prior to the index stroke, or other ischemic vascular disease.

Patients were randomly assigned 1:1 with a control group receiving usual care (n=207). In the invention group, patients received an ICM within 10 days of the index stroke and after randomization (n=210). The primary outcome measure was detection of AF over 12 months between study groups.

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There was a 12.1% (n=27) incidence of AF in the ICM group, compared with 1.8% (n=4) in the control group (hazard ratio [HR], 7.4; 95% CI, 2.6-21.3; P <.001). In the ICM group, 100% of AF episodes were detected by the ICM. In the control group, AF episodes were detected by 76 electrocardiograms in 57 patients, 26 Holter monitors/event recorders in 25 patients, and 2 mobile cardiac telemetry devices in 2 patients. There were 2 additional patients in the control group with possible AF episodes. Adding these patients to the sensitivity analyses still revealed a significantly increased AF detection incidence in the ICM group compared with the control group (HR, 4.9; 95% CI, 2.0-11.9; P <.001).

Limitations of this study include the subjective attribution of stroke mechanism, which may have led to enrollment of a population at higher risk of underlying embolism. The study was not sufficiently powered to detect a significant difference in rates of recurrent stroke. The use of electrocardiogram in follow-up in the control group was variable and limited, which reduced the ability to detect AF in these patients.

“In this randomized clinical trial, among patients with a recent ischemic stroke attributed to large- or small-vessel disease, monitoring with an ICM resulted in a significantly higher rate of AF detection compared with usual care at 12 months,” the researchers concluded. “The results presented are comparable to a small observational study of a noncryptogenic ischemic stroke cohort that found AF detected in 6 of 51 patients (12%) after monitoring with an ICM for 13 months.”

They added, “The present study provides evidence of the higher yield of AF detection by ICM in patients with noncryptogenic stroke starting within 10 days of the index stroke. However, further research is needed to understand whether identifying AF in these patients is of clinical importance.”

Disclosure: This research was supported by Medtronic, Inc. Please see the original reference for a full list of disclosures.


Bernstein RA, Kamel H, Granger CB, et al; for the STROKE-AF Investigators. Effect of long-term continuous cardiac monitoring vs usual care on detection of atrial fibrillation in patients with stroke attributed to large- or small-vessel disease. JAMA. 2021;325(21):2169-2177.