Late Gadolinium Enhancement-MRI determines definite lesion formation most accurately at three months post ablation compared to later time points.

Aims Neither the long-term development of ablation lesions nor the capability of late gadolinium enhancement (LGE) -MRI to detect ablation-induced fibrosis at late stages of scar formation have been defined. We sought to assess the development of atrial ablation lesions over time using LGE-MRI and invasive electroanatomical mapping (EAM). Methods and results Ablation lesions and total atrial fibrosis were assessed in serial LGE-MRI scans 3 months and >12 months post pulmonary vein (PV) isolation. High-density EAM performed in subsequent repeat ablation procedures served as a reference. Serial LGE-MRI of 22 patients were analysed retrospectively. The PV encircling ablation lines displayed an average LGE, indicative of ablation-induced fibrosis, of 91.7±7.0% of the circumference at 3 months, but only 62.8±25.0% at a median of 28 months post ablation (p 12 months post ablation. Accordingly, the agreement with EAM regarding detection of ablation-induced fibrosis and functional gaps was good for the LGE-MRI at 3 months (κ 0.74; p Conclusion While non-invasive lesion assessment with LGE-MRI 3 months post ablation provides accurate guidance for future redo-procedures, detectability of atrial ablation lesions appears to decrease over time. Thus, it should be considered to perform LGE-MRI 3 months post-ablation rather than at later time-points >12 months post ablation, like e.g. prior to a planned redo-ablation procedure. This article is protected by copyright. All rights reserved.