The Role of Cardiac Magnetic Resonance in Characterizing Atrial Cardiomyopathy and Guiding Substrate Ablation in Atrial Fibrillation: A Narrative Review.

Cardiac magnetic resonance imaging (MRI) is increasingly recognized as a promising tool for tissue characterization in atrial fibrillation (AF), providing detailed insights into anatomy, fibrosis, and scarring. While MRI cannot directly guide ablation lesions, its ability to identify arrhythmogenic substrates could improve patient stratification and procedural planning. Despite these theoretical advantages, the clinical utility of MRI in guiding substrate-based ablation strategies remains a matter of debate. Methods: Our review evaluates the current evidence supporting the integration of MRI into the workflow of AF ablation. Specifically, we examine findings from randomized trials and prospective studies that have investigated the predictive value of MRI-derived fibrosis quantification for procedural outcomes and arrhythmia recurrence. We aim to assess whether MRI can enhance the personalization of ablation strategies and predict treatment success. Challenges such as variability in imaging protocols, lack of standardization in fibrosis quantification, and limited large-scale validation are also addressed. This review provides a comprehensive overview of the current status and potential of MRI in the evolving field of AF ablation.