Intracardiac ECHO Integration With Three Dimensional Mapping

Background: Catheter ablation of atrial fibrillation (AF) is typically guided by 3D mapping. This
involves point-by-point reconstruction of the 3D virtual anatomy and may be time consuming and
require substantial fluoroscopy exposure. Intracardiac echocardiography (ICE) affords real time
imaging of the cardiac structures during mapping and ablation.
Methods: Between February and May 2007, 15 patients (100% men, 10 with paroxysmal AF)
presenting for AF ablation were offered mapping using a novel system integrating 3D mapping and
ICE. A modified ICE probe with a location sensor tracked by the mapping system was positioned in
the right atrium (RA). This allowed acquisition of ECG gated images of the left atrium (LA).
Endocardial contours were traced on each image and were used to generate a registered 3D map.
Results: 3D maps took a mean of 51+/-25 minutes to create, PRIOR to entering the LA and without
fluoroscopy. Pulmonary veins and the esophagus were rendered in 3D. A complete map was built from
a mean of 46+/-19 contours. Upon instrumentation of the left atrium, the maps were easily distorted if
points collected by the mapping catheter were combined with the original map, due to deformation of
the left atrial geometry by the relatively stiff ablation catheter. Pulmonary vein antrum isolation was
guided by a circular mapping catheter. Since this catheter could not be visualized on the CARTO map,
fluoroscopy was used to track its position and the contact between the ablation catheter and the circular
mapping catheter. No substantial reduction in fluoroscopy time was thus realized, as expected. At
10+/-1 months of followup, 73% of the patients were in sinus rhythm after the initial three month
blanking period. No patient suffered any complications related to the procedure or in follow-up.
Conclusions: A mapping system combining ICE and 3D electroanatomical mapping can feasibly
reconstruct a 3D shell of the LA and the pulmonary veins without the need to enter the left heart. The
map created is sensitive to distortion during point-by-point mapping with the standard ablation
catheter.