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Implantable vs. Prolonged External ECG Monitoring on AF Detection in Stroke
Quick Takes
- In this randomized clinical trial, the rate of detection of atrial fibrillation (AF) or flutter lasting 2 minutes or longer by 12 months was 15.3% in the implantable loop recorder group vs. 4.7% in the 30-day external loop recorder group, a difference which was statistically significant.
- Unlike prior studies evaluating the implantable loop recorders in patients with stroke and no AF, the present study did not exclude patients with other causes of stroke (i.e., only 66% of patients had a stroke of undetermined etiology).
Study Questions:
In patients with a recent ischemic stroke, does 12 months of implantable loop recorder monitoring detect more occurrences of atrial fibrillation (AF) compared with conventional external loop recorder monitoring for 30 days?
Methods:
A total of 300 patients, who recently experienced ischemic stroke in the absence of documented AF, were randomly assigned 1:1 to prolonged electrocardiographic (ECG) monitoring with either an implantable loop recorder (n = 150) or an external loop recorder (n = 150) with follow-up visits at 30 days, 6 months, and 12 months.
Results:
Among the 300 patients who were randomized (median age, 64 years; 40% were women), 66.3% had a stroke of undetermined etiology with a median CHA2DS2-VASc score of 4). AF on monitoring during follow-up was observed in 15.3% of patients in the implantable loop recorder group and 4.7% of patients in the external loop recorder group (risk ratio, 3.29; p = 0.003). Five patients (3.3%) in the implantable loop recorder group had recurrent ischemic stroke versus eight patients (5.3%) in the external loop recorder group. The incidence of intracerebral hemorrhage was the same in each group (2%).
Conclusions:
Among patients with ischemic stroke and no prior evidence of AF, implantable ECG monitoring for 12 months, compared with prolonged external monitoring for 30 days, resulted in a significantly greater proportion of patients with AF detected over 12 months.
Perspective:
The detection of AF after ischemic stroke is very important diagnostically, as it has been shown that there is a risk reduction of recurrent stroke among patients with AF who are started on oral anticoagulation. Prior studies evaluating ambulatory monitoring for detection of AF post stroke were confined to patients in whom stroke was cryptogenic after a thorough workup failed to reveal any potential causes of stroke such as large-vessel or small-vessel disease, etc. The present study is more clinically applicable because it enrolled all stroke patients, as long as they did not have known AF, and it was the first head-to-head study looking at the detection rates of a 30-day external loop recorder versus an implantable loop recorder analyzed at 12 months. The findings of this study are unsurprising, but at the same time they are informative in terms of the magnitude of the AF detection. All AF diagnoses in the study resulted in new prescriptions for anticoagulation. Further work is needed to compare clinical outcomes and relative cost-effectiveness associated with a 30-day event monitor and an implantable loop recorder.
Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure
Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Brain Ischemia, Cerebral Hemorrhage, Cost-Benefit Analysis, Electrocardiography, Heart Failure, Monitoring, Ambulatory, Myocardial Ischemia, Prescriptions, Risk Reduction Behavior, Vascular Diseases
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