An ischemic stroke is caused by thrombosis of the cerebral vessels or by emboli from a proximal arterial source or the heart. This blockage deprives the brain cells of vital oxygen and nutrients leading to cell death. A transient ischemic attack (TIA) is a neurological deficit lasting less than 24 hours, caused by cerebral ischemia.
Atrial fibrillation (AF) is a type of cardiac arrhythmia, which causes pooling of blood that leads to thrombosis formation and may cause a stroke or TIA. Patients with AF but no history of stroke have a stroke risk of 4.5% per year; however, anticoagulation therapy, can reduce this risk to 1.4% per year. Often patients with AF will not have any symptoms, and therefore they are difficult to identify. Roughly 30% to 40% of first-time ischemic strokes are due to an unknown cause, and are referred to as an embolic stroke of undetermined source (ESUS). Patients who have experienced ESUS may have undiagnosed, or occult, AF. Determining whether they do have AF can be important to help prevent future strokes or TIAs.
Long-term electrocardiography (ECG) monitoring using outpatient cardiac monitoring devices can identify occult AF that is undetectable by other means. To this end, outpatient cardiac monitoring devices providing increased mobility for patients and the ability to transmit data wirelessly have been developed, and allow for longer-term surveillance outside the hospital setting. These devices include ambulatory Holter monitors, external loop recorders (ELRs), mobile cardiac outpatient telemetry (MCOT) devices, and implantable loop recorders (ILRs).
CADTH conducted a health technology assessment (HTA) on the clinical effectiveness and cost-effectiveness of cardiac monitoring devices in patients discharged from hospital following a stroke or TIA, to help inform decisions about these devices. Patient perspectives and experiences regarding the value and impact of outpatient AF cardiac monitoring devices were also considered.
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