Embolic Stroke of Undetermined Source (ESUS) is used to describe patients with cryptogenic stroke despite adequate diagnostic work-up, i.e. non-lacunar strokes without proximal arterial stenosis or a major cardiac source of embolism like atrial fibrillation (AF), mechanical heart valves and others [1,2]. Approximately 17% of all patients with ischemic stroke have an ESUS [1]. This type of ischemic stroke has the highest rate of stroke recurrence with approximately 5% per year [1,3,4]. Among other potential etiologies, episodes of covert AF can be an underlying cause of ESUS [2,5].
