Abstract
Backgrounds: Localization of the esophagus and the left atrium
(LA) posterior wall thickness (LAPWT) should be taken into account when
delivering radiofrequency energy. Intracardiac echo (ICE) advanced into
the LA is useful in visualizing LA and surrounding structure by its high
and real-time resolution.
Methods: In 73 patients (mean age, 68±12; paroxysmal AF in 45),
3-dimensional (3D) esophagus image was created with CARTO
SoundstarⓇ and its location was compared with contrast
esophagography saved in Carto UNIVU™. LAPWT adjacent to the esophagus
was measured at 4 levels: left superior PV (LSPV), intervenous carina
(IC), left inferior PV (LIPV), and LIPV bottom. A target AI value was
260 (25W power) on the esophagus region.
Results: All patients had the esophagus posterior to the left
PV antrum. Creating 3D esophagus and measurement of LAPWT with ICE was
done without any complications. ICE esophagus image was completely
overlapped with contrast esophagography. LAPWT (mm) was 2.8
(interquartile range, 2.5-3.2), 2.2 (1.9-2.5), 1.9 (1.8-2.1), and 2.1
(1.9-2.4) for LSPV, IC, LIPV and LIPV bottom, respectively, while LA
roof thickness 3.2 (2.9-3.6) (P<0.0001 by ANOVA). No residual
conduction gap on the esophagus after the first circumferential PV
isolation was found in 64 of 73 (88%) patients.
Conclusions: ICE inserted into the LA can reliably locate and
display the esophagus and its relationship to the LA. LAPWT was thinnest
at LIPV level. AI-guide ablation targeting a relatively low target AI
value 260 on the esophagus seemed to be effective.
Keywords: Radiofrequency ablation; left atrial posterior wall;
esophagus; ablation index; intracardiac echo