Occult atrial fibrillation in ischemic stroke

Physicians frequently evaluate patients with recent ischemic strokes or transient ischemic attacks (TIA) and perform diagnostic evaluations only to find no clear demonstrable etiology in fully one-third of cases. Cryptogenic stroke remains a diagnostic category of exclusion and encompasses a broad range of patients with varied risk factors, comorbid conditions, and radiographic patterns of cerebral infarction. In contrast, atrial fibrillation (AF) is a common and well-defined cause of ischemic stroke, representing 50% of cardioembolic stroke and 10% of all ischemic strokes, often resulting in severe neurologic disability.¹ AF can be readily diagnosed by electrocardiography, and has known risk factors, pathophysiology, and therapeutic options, including anticoagulation. Approximately 25% of patients with AF have intermittent AF that is often asymptomatic and undetected by conventional methods of brief cardiac telemetry monitoring.^1,2 Patients who are initially diagnosed with cryptogenic stroke or TIA can be found subsequently to have intermittent AF, suggesting that efforts to improve AF detection are warranted. An optimal telemetry monitoring method for the detection of occult AF could identify stroke patients at risk for recurrent cardioembolic stroke and a subgroup that may benefit from anticoagulation.

Paroxysmal AF (PAF) is believed to carry the same stroke risk as continuous AF; however, patients with PAF exhibit a …