Left Atrial Remodelling in Atrial Fibrillation: Correlation Between Magnetic Resonance Imaging and High-Density Electroanatomic Mapping

Introduction : The extent of left atrial (LA) fibrosis is a key indicator of atrial fibrillation (AF) progression. It can be assessed using magnetic resonance imaging (MRI) or invasive electroanatomical (EA) mapping. This study aims to examine the correlation between these two methods. Methods A consecutive cohort of patients with non-paroxysmal AF and an indication for a first-time catheter ablation was enrolled. All patients underwent cardiac MRI within two months prior to the procedure. The scans were analysed using the ADAS software. During the ablation, high-density EA mapping of the left atrium was carried out using the OCTARAY™ catheter. MRI scans and EA maps were analysed semiquantitatively and point-by-point, and their correlation was assessed. Results Twenty-one patients were analysed (median age 70 years [IQR: 66–73]), 71% males, 12 (57%) long-standing persistent AF). In 76% of cases, EA mapping was performed during AF, with the median number of acquired points being 3,388 (IQR: 2,929–4,475). No correlation was found when comparing the results of semiquantitative (R = 0.06) and point-by-point (median R across all cycles − 0.0745 [IQR: −0.1156 to − 0.0273]) analysis. MRI scans showed significantly fewer fibrotic changes compared to EA maps. Conclusions In the cohort of long-standing persistent AF patients presented, we did not find a correlation between MRI scans and high-density EA maps. The extent of fibrotic changes detected by EA mapping was higher compared to cardiac MRI scans.