Relationship between the posterior atrial wall and the esophagus: Esophageal position during atrial fibrillation ablation

Abstract

Background: Atrial fibrillation ablation implies a risk of esophageal thermal injury. Esophageal position can be analyzed with imaging techniques, but evidence for esophageal mobility is inconsistent.

Objectives: The purpose of this study was to analyze esophageal position stability from one procedure to another and during a single procedure.

Methods: Esophageal position was compared in 2 patient groups. First, preprocedural multidetector computerized tomography (MDCT) of first pulmonary vein isolation and redo intervention (redo group) was segmented with ADAS 3D™ to compare the stability of the atrioesophageal isodistance prints. Second, 3 imaging modalities were compared for the same procedure (multimodality group): (1) preprocedural MDCT; (2) intraprocedural fluoroscopy obtained with the transesophageal echocardiographic probe in place with CARTOUNIVU™; and (3) esophageal fast anatomic map (FAM) at the end of the procedure. Esophageal position correlation between different imaging techniques was computed in MATLAB using semiautomatic segmentation analysis.

Results: Thirty-five redo patients were analyzed and showed a mean atrioesophageal distance of 1.2 ± 0.6 mm and a correlation between first and redo procedure esophageal fingerprint of 91% ± 5%. Only 3 patients (8%) had a clearly different position. The multi-imaging group was composed of 100 patients. Esophageal position correlation between MDCT and CARTOUNIVU was 82% ± 10%; between MDCT and esophageal FAM was 80% ± 12%; and between esophageal FAM and CARTOUNIVU was 83% ± 15%.

Conclusion: There is high stability of esophageal position between procedures and from the beginning to the end of a procedure. Further research is undergoing to test the clinical utility of the esophageal fingerprinted isodistance map to the posterior atrial wall.

Keywords: Atrial fibrillation; Atrial wall thickness; Atrioesophageal fistula; Catheter ablation; Esophageal position.

Graphical abstract

Figure 1

Study group design. Top: Group 1 redo: Comparison of atrioesophageal relationship as seen by the esophageal isodistance fingerprinted map, between preprocedural MDCT at first and redo ablations. Bottom: Group 2 multimodality: Comparison of 3 different imaging methods for the same procedure. Left: Anteroposterior fluoroscopic view with superposed esophageal anatomy segmented from the MDCT and atrial anatomy in glass mode. Center: Anteroposterior fluoroscopic view with the transesophageal echocardiographic probe inserted in the esophagus. Right: Anteroposterior fluoroscopic view with superposed esophageal fast anatomic map (ESO-FAM) obtained with the ablation catheter. MDCT = multidetector computerized tomography.

Figure 2

Segmentation pipeline of the fingerprinted atrioesophageal isodistance map. 1: Raw MDCT DICOM images were imported into ADAS 3D for segmentation. 2: Complete 3-dimensional (3D) reconstruction of the esophageal and atrial anatomy was obtained. 3: The atrioesophageal fingerprinted isodistance map was projected onto the atrial endocardial surface (atrioesophageal distance: red <1 mm; yellow 1–2 mm; green 2.1–3 mm; blue 3.1–4 mm; purple >4.1 mm). MDCT = multidetector computerized tomography.

Figure 3

Esophageal position acquisition methods. 1: Left: Three-dimensional MDCT-derived esophageal anatomy with color-coded atrioesophageal distance gradient (red <1mm; yellow 1–2 mm; green 2.1–3 mm; blue 3.1–4 mm; purple >4.1 mm). Center: UNIVU anteroposterior acquisition with the transesophageal echocardiographic probe in place. Right: Esophageal fast anatomic map (FAM) obtained with the ablation catheter. 2: Image integration into the navigator. Merging of the atrial FAM with the MDCT-derived left atrial wall thickness map using the CARTOMERGE module. 3: Mean image correlation between methods. MDCT = multidetector computerized tomography.

Figure 4

Group 1 (MDCT) results of esophageal fingerprinted isodistance map correlation. Top: Case with low correlation. Note the esophageal fingerprint contour in blue for the first ablation and in red for the redo procedure. Bottom: Case with high correlation of esophageal fingerprint between first and redo procedures (95% image correlation). MDCT = multidetector computerized tomography.

Figure 5

Group 2 (multimodality ) results. Top: High image correlation. Bottom: Low image correlation). 1: Anteroposterior UNIVU acquisition with transesophageal echocardiographic probe in place. 2: Correlation between MDCT and CARTOUNIVU. 3: Correlation between MDCT and esophageal FAM. 4: Correlation between MDCT and esophageal FAM. FAM = fast anatomic mapping; MDCT = multidetector computerized tomography.