Is there a temporal relationship between atrial fibrillation and stroke? A review

Importance: Atrial fibrillation (AF) is an established risk factor for ischaemic stroke. The introduction of continuous cardiac rhythm monitoring devices has enabled detection of brief and asymptomatic episodes of AF. Observations: The search yielded 727 studies, 11 of which met the inclusion criteria. Four studies suggested a strong temporal association between episodes of AF and stroke, while seven indicated a weak relationship. The conflicting nature of the studies may be attributed to inconsistencies in ischaemic stroke verification (n=5/11), event rate and power (n=6/11) and lack of controlling for anticoagulation (n=10/11), mitigating the relationship between AF episodes and stroke. Conclusions and relevance: The temporal relationship between AF and stroke still remains unclear due to varying study methodology, lack of control for anticoagulation and inconsistent stroke subtyping. Our review identifies limitations to the current literature and makes recommendations for future studies assessing the temporal relationship between AF episodes and cardioembolic stroke.