Anatomical localization and progression of silent cerebral embolic lesions following transcatheter ablation of atrial fibrillation.

Purpose: Silent cerebral embolic lesions (SCELs) are a frequent complication of atrial fibrillation (AF) transcatheter ablation (TA) but little is known about their anatomical features and whether these lesions persist at follow-up is controversial. The aims of this study were to examine the pattern of anatomical localization of SCELs following TA of AF and their clinical course by means of cerebral MRI. Methods: 85 patients with paroxysmal/persistent AF with newly documented SCELs at post-TA cerebral MRI were included in this analysis. Localization, number, size of SCELs were recorded and Voxel based morphometry (VBM), a MRI whole-brain measurement technique, was used to study SCELs localization in relation to brain regions. After a mean of 5.3 months, 26 patients underwent repeat MRI scans and neurological assessment to ascertain persistence of SCELs and their clinical impact. Results: Overall, 145 SCELs were counted at post-TA cerebral MRI (1.7 SCELs/patient) without overt neurological symptoms. The number of SCELs was significantly higher in patients with long-term persistent AF compared with those affected by paroxysmal/persistent AF (3.0±0.8 vs. 1.6±1.0, p=0.02). The majority of SCELs showed cortical localization (88.3% vs. 11.7% subcortical, p<0.001) and the regions more frequently involved were the parietal lobe (43 SCELs, 29.7%) and the frontal lobe (38 SCELs, 26.2%) as confirmed by VBM (Fig. 1). In patients undergoing follow-up MRI, almost half (48.8%) of the lesions were still detectable showing only minimal size reductions. Discussion: Considering the cortical localization and persistence of SCELs, greater attention should be paid to the potential long-term neurological impact of such lesions. Prospective studies investigating SCELs' influence on cognitive function are warranted.