• 3D ultrasound mapping;
  • anatomic distortion;
  • atrial fibrillation;
  • catheter ablation;
  • contact force sensing;
  • electroanatomic mapping

Anatomic Distortion of 3D Mapping. Background: Although catheter tip-tissue contact is known as a reliable basis for mapping and ablation of atrial fibrillation (AF), the effects of different mapping methods on 3-dimensional (3D) map configuration remain unknown.

Methods and Results: Twenty AF patients underwent Carto-based 3D ultrasound (US) evaluation. Left atrium (LA)/pulmonary vein (PV) geometry was constructed with the 3D US system. The resulting geometry was compared to geometries created with a fast electroanatomical mapping (FAM) algorithm and 3D US merged with computed tomography (merged 3D US-CT). The 3D US-derived LA volumes were smaller than the FAM- and merged 3D US-CT-derived volumes (75 ± 21 cm3 vs 120 ± 20 cm3 and 125 ± 25 cm3, P < 0.0001 for both). Differences in anatomic PV orifice fiducials between 3D US- and FAM- and merged 3D US-CT-derived geometries were 6.0 (interquartile range 0–9.3) mm and 4.1 (0–7.0) mm, respectively. Extensive encircling PV isolation guided by 3D US images with real-time 2D intracardiac echocardiography-based visualization of catheter tip-tissue contact generated ablation point (n = 983) drop-out at 1.9 ± 3.8 mm beyond the surface of the 3D US-derived LA/PV geometry. However, these same points were located 1.5 ± 5.4 and 0.4 ± 4.1 mm below the FAM- and merged 3D US-CT-derived surfaces.

Conclusions: Different mapping methods yield different 3D geometries. When AF ablation is guided by 3D US-derived images, ablation points fall beyond the 3D US surface but below the FAM- or merged 3D US-CT-derived surface. Our data reveal anatomic distortion of 3D images, providing important information for improving the safety and efficacy of 3D mapping-guided AF ablation. (J Cardiovasc Electrophysiol, Vol. 24, pp. 259-266, March 2013)