Short term atrial fibrillation in different stroke entities

Background Stroke including ESUS is one of the most common causes of disability and death in the world. Atrial fibrillation (AF) of more than 30 sec is considered a reason for cardioembolic stroke. Nevertheless, shorter periods of AF might also be a possible risk factor. Methods We determined periods of AF within a range of 0-14 s, 15-30 s and > 30 s in patients with different stroke entities. We analysed all ischemic strokes and transient ischemic attacks at the Stroke Units/Emergency Room in Siegen within 6 months and classified them etiologically. All stroke patients were prospectively ECG monitored over a minimum of 24h and characterized for the different AF periods at the stroke unit. The stroke entities were then compared. RESULTS A number of 714 patients over 6 months were hospitalized suffering a stroke. Among them 163 (30.8%) had a cryptogenic Stroke, including 98 (19%) ESUS patients. Furthermore, 185 (26%) TIA, 209 (39%) cardioembolic, 110 (21%) atherosclerotic, 40 (8%) lacunar and 7 (1%) other specific strokes were registered. Manifest atrial fibrillation (>30s) showed a prevalence of 23% within our stroke population. Whereas 15% had an AF episode of 15-29 s and 16% presented AF episode of 0-14 s. Among cardioembolic infarcts, 45% had manifest atrial fibrillation (>30 s), 20% had an atrial fibrillation episode of 15-29 s, and 22% showed an atrial fibrillation episode of 0-14 s. Taken together, more than 90% of cardioembolic infarcts show an episode of atrial fibrillation of any duration. An AF episode of 15-29 s or 0-14 s was also found in almost 35% of ESUS patients: similar to cryptogenic infarctions. In 22% of the TIA patients manifest atrial fibrillation had been detected. 7% of TIA patients showed one or more episodes of AF of 15-29 s and 10% an episode of 0-14 s. Among the atherosclerotic infarctions, the proportion of AF >30 s is profoundly lower at 12%, however the percentage of AF for 15-29 s was 14. The smallest ratio of atrial fibrillation of any duration was formed by lacunar insults with a total of nearly 25%, of which only 13% had manifest AF. Conclusion Non-valvular atrial fibrillation presents the most common cause of cardiac cerebral embolism. In our study, AF showed the largest ratio among cardioembolic strokes with 48%. Overall, AF of any duration occurred in nearly 90% of this group. Since a manifest AF is an exclusion criterion for ESUS, conversely, none of the ESUS patients suffered from manifest AF. However, it is striking that 15% of ESUS patients had an AF episode of 15-29 s and 18% had an AF episode of 0-15 s. Similar results were observed in cryptogenic strokes. Possibly, the definition of AF has to be adjusted, since the stroke subgroups with short term AF did not receive proper anticoagulation treatment. However, at least advanced rhythm monitoring should be provided. This should be investigated in future prospective studies.