New Insights Into the Use of Cardiac Magnetic Resonance Imaging to Guide Decision Making in Atrial Fibrillation Management

Recent advances in cardiac magnetic resonance (CMR) imaging acquisition techniques have enabled the visualization of thin atrial myocardium with high temporal and spatial resolution and have the potential to shift atrial fibrillation (AF) management paradigms. Late gadolinium-enhancement (LGE)-CMR can noninvasively identify atrial arrhythmogenic scar substrates and has been shown to spatially correlate with low-voltage areas. Immediately after ablation, a combination of native T1-weighted, LGE, and T2-weighted imaging can assess ablation lesions and localize reversible edema, whereas late after ablation, LGE-CMR can visualize irreversible fibrosis and detect large ablation gaps. Tissue tracking on cine-CMR can be used to characterize the impact of ablation and AF-related remodelling on atrial structure and contractile function. Increased burden of “native” LGE and lower left atrial function at baseline are associated with worse procedural outcomes, and identification of patients with the greatest fibrotic extent may improve patient selection for AF ablation procedures or identify a subset of patients for whom pulmonary vein isolation alone is unlikely to be beneficial. Left atrial appendage morphology and left atrial sphericity index may provide additional prognostic information in AF ablations. A suggested approach for patients with extensive fibrosis includes substrate modification in addition to pulmonary vein isolation. Another approach involves virtual electrophysiological simulation of AF, localization of computationally derived AF drivers, and determination of optimal ablation targets for persistent AF suppression. Finally, both LGE-CMR and cine-CMR have offered invaluable insights into AF-related stroke mechanisms and may enhance available prediction models that guide anticoagulation therapy.