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 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. While
the maps were precise prior to instrumentation of the left atrium, they 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.
Credits: Yaariv Khaykin, MD; Allan Skanes, MD; Zaev A. Wulffhart, MD; Lorne Gula, MD; Bonnie Whaley, CVT; Richard Oosthuizen; Catherine Seabrook, RN; Marianne Beardsal, RN; Atul Verma, MD.