P1080Magnetic resonance imaging after electrical cardioversion of recent-onset atrial fibrillation in anticoagulant-naive patients - a study exploring clinically silent cerebral lesions

Abstract Funding Acknowledgements Unrestricted grants from the Swedish Heart-Lung Foundation, the Swedish Research Council, Correvio International Sárl (CH) and Selanders stiftelse Background Patients with atrial fibrillation (AF) have a high incidence of cognitive impairment, which may be related to clinically silent microembolism causing cerebral infarctions. Purpose To explore the occurrence and timing of silent brain lesions following electrical cardioversion (CV) of recent onset AF in anticoagulant-naïve patients and to further study related effects on cognitive function and biomarkers of cerebral damage, S100b. Methods Patients with AF duration < 48 hours were prospectively included. Brain magnetic resonance imaging (MRI) and S100b, were obtained prior, after and 7-10 days following CV. Trail making tests (TMT-A and TMT-B) and their difference, ΔΤΜΤ, were assessed prior to CV, 7-10 days and 30 days after CV. Results Forty-three patients (84% males) with mean CHA2DS2-VASc score 0.6 ± 0.7 were included. Sequential MRI, including diffusion weighted scans, showed no new brain lesions after CV. Chronic white matter hyperintensities (WMH) were present at baseline in 21/43 (49%) patients. By partitioning the study population into four major groups according to the extend of WMH (Fazekas score 0 or ≥ 1) and the presence or absence of TE risk factors (CHA2DS2-VASc score 0 or ≥ 1), the TE risk as defined by CHA2DS2-VASc score ≥ 1, was associated with a higher incidence of WMH, Pearson χ2(1,N = 43)=3.95, p = 0.047. The S100b (µg/l) levels increased significantly from baseline, (mean ± SD) 0.0472 ± 0.0182 to 0.0551 ± 0.0185 after CV, p = 0.001 and then decreased 7-10 days after CV to 0.0450 ± 0.0186, p < 0.001. Subgroup analysis according to the presence of at least one TE risk factor as defined by CHA2DS2-VASc score showed that statistical significance of repeated measures ANOVA was maintained; for patients with no risk factors F (2,30)=12.59, p < 0.001 and for patients with CHA2DS2-VASc score ≥1 F(2,36)=4.43, p < 0.019. Consecutive TMT scores improved successively after CV, being statistically and clinically significant for TMT-B (p < 0.01) and ΔΤΜΤ (p = 0.005) between 7-10 days and 30 days after CV (Reliable Change Index >1.96). Conclusion New brain lesions could not be detected on MRI after CV, but the high incidence of white matter hyperintensities and the transient increase in S100b may indicate transient or minor brain damage undetectable by MRI thus heightening the need to reevaluate thromboembolic risk prior to CV even in low risk patients. Abstract Figure. S100b_TMT