Paroxysmal Atrial Fibrillation in Cryptogenic Stroke: an Overlooked Explanation?

Approximately one third of ischemic strokes are labeled cryptogenic because the etiology is unknown despite a thorough evaluation. Paroxysmal atrial fibrillation carries the same risk of ischemic stroke as persistent atrial fibrillation and has increasingly gained attention as a potential source of cryptogenic stroke. Recent trials utilizing long-term cardiac monitoring devices have demonstrated high rates of previously undetected paroxysmal atrial fibrillation in patients with cryptogenic stroke. Newly detected atrial fibrillation has subsequently changed treatment and increased the use of oral anticoagulation in these studies. Other trials have shown an increased risk of stroke and thromboembolism in patients with device-detected subclinical tachyarrhythmias. Together, these studies suggest an important relationship between episodes of paroxysmal atrial fibrillation and the risk of cryptogenic stroke, but further investigations are needed to guide diagnostic and therapeutic decisions.