Left atrial geometry in atrial Fibrillation: A comparison between electroanatomical mapping and computed tomography

Area of Science:

• Cardiology
• Medical Imaging
• Computational Anatomy

Background:

• Atrial fibrillation (AF) involves complex left atrial (LA) remodeling, necessitating precise geometric quantification.
• Computed Tomography (CT) is the gold standard for anatomical assessment.
• Electanatomical mapping (EAM) offers intraprocedural reconstruction with electrophysiological data, but its anatomical agreement with CT is not fully understood.

Purpose of the Study:

• To compare the geometric accuracy of LA reconstructions derived from EAM against CT.
• To quantify the agreement and discrepancies between CT and EAM in LA geometry.

Main Methods:

• Retrospective analysis of 211 patients undergoing first-time catheter ablation with pre-procedural CT.
• Derivation of LA volume, surface area, and sphericity from both CT and EAM datasets.
• Comparison using Pearson correlation, Bland-Altman analysis, RMS radial differences, and Dice similarity on original meshes and ellipsoidal models.

Main Results:

• EAM showed moderate correlation with CT for LA volume (r=0.58), area (r=0.56), and sphericity (r=0.49).
• Bland-Altman analysis revealed systematic overestimation of LA volume (13.2%) and surface area (9.6%) by EAM, with slight underestimation of sphericity (-0.01).
• Ellipsoidal approximations showed better agreement (higher Dice similarity) than original meshes, indicating preserved global shape despite scale differences.

Conclusions:

• EAM provides a rapid, albeit approximate, intraprocedural assessment of LA geometry.
• Significant systematic scale differences and local discrepancies exist between EAM and CT-derived LA anatomy.
• EAM serves as a valuable complementary tool to CT for LA assessment, rather than a direct substitute.