Diagnostic yield of external loop recording in patients with acute ischemic stroke or TIA.

Atrial fibrillation (AF) is a strong risk factor for first-ever stroke and stroke recurrence. The detection rate is low and detection is often costly and time-consuming. We evaluated the diagnostic yield of an external loop recorder (ELR) in patients with acute ischemic stroke or TIA, and assessed factors that are associated with AF detection. We prospectively studied patients admitted to the stroke unit with ischemic stroke or TIA, without a history of AF, and no AF on routine-ECG and 24-h telemetry. Patients received an ELR for another 24-h registration. Rhythm registration with an ELR was performed in 94 patients. AF was identified in 5 patients (5 %). AF was associated with cryptogenic stroke and cortical or subcortical involvement. If ELR was limited to patients with cryptogenic stroke in combination with cortical or subcortical involvement, the detection rate increased to 17 %. Automated recording with ELR was easy to use in the acute setting of ischemic stroke or TIA and seems promising to detect AF or atrial flutter, in particular in patients with cryptogenic stroke in combination with cortical or subcortical symptoms.

Performance of an external transtelephonic loop recorder for automated detection of paroxysmal atrial fibrillation.

BACKGROUND: Although atrial fibrillation (AF) is the most commonly encountered arrhythmia, some of the properties make its detection challenging. In daily practice, underdiagnosis can lead to less effective treatment in prevention of stroke. Based on data from studies on treatment of AF, more intensive follow-up strategies, including 7-day Holter recording, 30-day event recording, and even implantable cardiac monitoring devices, are suggested. The study purpose is to evaluate the performance of a continuous single-channel loop recorder with automatic AF detection and transtelephonic electrocardiogram (ECG) transmission capabilities. METHODS AND RESULTS: A consecutive cohort of 153 patients admitted to the stroke unit with a presumptive diagnosis of ischemic cerebrovascular accident was screened for AF. Twenty-four-hour rhythm observation was performed using a single-channel external loop recorder (ELR) configured for automated AF detection. A total of 45 patients with a known history of AF, AF on the admission ECG, or incomplete registrations were excluded. Extensive additional frequency-based settings were used to establish a reference registration. In total, 2923 recordings were transmitted. We evaluated all events, of which 1190 were designated by the device as AF. The sensitivity, specificity, PPV, and NPV for identifying AF using the ELR were, respectively, 93%, 51%, 5%, and 99%. CONCLUSIONS: In this ELR validation study, the dedicated AF detection algorithm showed to be highly sensitive but not specific for AF. Applicability of an ELR might be limited for efficacious detection of AF, as manual verification is mandatory for a vast amount of recordings.