This editorial refers to ‘Cardiac magnetic resonance and electroanatomical mapping of acute and chronic atrial ablation injury: a histological validation study’, by J.L. Harrison et al. doi:10.1093/eurheartj/eht560. The advent of catheter ablation for atrial fibrillation (AF) has revolutionized our approach to this most common of arrhythmias, and in selected instances the procedure is now considered first-line therapy. Indeed, over the past decade, tools and techniques have evolved to the stage where this procedure is routinely offered to many patients with refractory paroxysmal and early persistent AF. However, the recurrence rate following ablation continues to present an ongoing challenge with need for repeat ablation procedures in anywhere between 20% and 50% of patients. While there may be many reasons for recurrence, key amongst these is the development of recurrent pulmonary vein (PV) to left atrial (LA) connection. Over recent years, the success in cardiac magnetic resonance (CMR) imaging of ventricular scar has led to attempts to reproduce these results in the atrium. In particular, a number of studies have used CMR late gadolinium enhancement (LGE) in order to characterize non-invasively the extent and distribution of scarring present following AF ablation.1–3 However, translation of the excellent results obtained from CMR imaging of ventricular scar to the atrium has faced the considerable hurdles associated with image resolution in a thin-walled structure and the absence of a widely available and standardized protocol for analysis of atrial scar. Several studies demonstrated that CMR could identify the extent of LA scarring present at 3 months post-ablation and observed that patients with more extensive scar (or greater percentage scar around the PV circumference) had a lower AF recurrence rate.2,4 In addition, there appears to be a correlation between measured contact force at the time of ablation and the extent of CMR-determined …