Nonsustained Atrial Fibrillation in Ischemic Stroke Patients and Stroke‐Free Controls From the Perspective of Stroke Pathophysiology

Abstract

Background Short‐lasting (<30 s), nonsustained episodes of atrial fibrillation ( NS ‐ AF ) are considered a risk factor for future development of paroxysmal or persistent AF . Nonetheless, their causal role in stroke pathogenesis is currently unknown. In this study we determined the frequency of NS ‐ AF , together with the associated clinical and imaging features, in stroke‐free controls and ischemic stroke patients. Methods and Results A total of 332 controls, ≥50 years of age and no prior history of stroke or AF , were evaluated with 24‐hour Holter monitoring for the presence of <30‐s‐long AF episodes. The demographic and cardiovascular features of this cohort, together with imaging finding on magnetic resonance imaging, were compared to a consecutive series of ≥50‐year‐old ischemic stroke patients without AF (n=498). The prevalence of NS ‐ AF was significantly higher among ischemic stroke patients in comparison to controls (37% versus 27%; P =0.002). In multivariable analyses, after adjustment for demographic and cardiovascular risk factors, patients with ischemic stroke were more likely to harbor NS ‐ AF episodes (odds ratio 1.43; 95% CI 1.01–2.02; P =0.041). The association between ischemic stroke and NS ‐ AF weakened when the analyses were restricted to cryptogenic stroke patients (odds ratio 1.31; 95% CI 0.82–2.08). No significant association was observed between the presence of chronic cortical infarcts and NS ‐ AF . Conclusions Our study shows a higher prevalence of NS ‐ AF episodes in ischemic stroke patients in comparison to controls. Nonetheless, the lack of a stronger association with cryptogenic strokes and absence of a relationship with chronic cortical infarcts brings into question the causal influence of NS ‐ AF in the ischemic stroke setting.