ELECTROPHYSIOLOGY
Visualization of the oesophagus in relation to the left atrium: an alternative concept
1 Division of Cardiology, Kantonsspital Luzern, 6000 Luzern 16, Switzerland; 2 Institute of Radiology, Kantonsspital Luzern, 6000 Luzern 16, Switzerland
Manuscript submitted 5 June 2006. Accepted after revision 27 September 2006.
* Corresponding author. Tel: +41 412055208. E-mail address: paul.erne{at}ksl.ch
Key Words: Catheter ablation, Oesophagus, Left atrium
Percutaneous catheter ablation of atrial fibrillation with radiofrequency (RF) energy-induced lines in the left atrium (LA) is increasingly used. With this technique, RF energy applications may occur in the close vicinity of the oesophagus and, albeit rarely, cause oesophageal perforation.1
Because this is a potentially lethal complication, integration of oesophageal reconstruction into the electro-anatomical LA map for visualization of the anatomical relationship is increasingly practised. As shown by Mönnig et al.,2 the position of the oesophagus manifests high variability in relation to the LA and the pulmonary veins. Tagging of the oesophagus by means of guiding a second 3-D mapping catheter through a conventional gastric tube into the oesophagus has been described.3 Alternatively, 3-D reconstruction of the oesophagus by multi-slice computed tomography (CT) after ingestion of barium is practised. However, barium ingestion induces peristalsis of the oesophagus, which may overestimate oesophageal mobility.
We present a concept for visualization of the oesophagus by multi-slice CT without the need for barium ingestion. A conventional radio-opaque gastric tube provides information about the course of the oesophagus in relation to the LA and may be scanned by multi-slice CT. A widely used 3-D electro-anatomical mapping system (Carto Merge®, Biosense Webster, Diamond Bar, CA, USA) allows integration of this anatomical information from the CT scan into the 3-D map (Figure 1). We propose this approach because visualization and integration of the oesophagus into the 3-D mapping system from a CT scan are not normally possible without the use of contrast in the oesophagus, by whatever means.
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The advantages of our concept are that the patient need not swallow barium paste and the cost of a second 3-D mapping catheter for tagging the oesophagus by a gastric tube is eliminated. As the issue of precise registration of the CT into the electrophysiological mapping system is not yet solved or standardized, proving concordance of our new concept of visualization of the oesophagus requires further studies. There are potential limitations to our concept. The electrophysiologist must be aware that the oesophagus is a mobile structure, and, therefore, a CT scan acquired prior to the ablation procedure may not accurately reflect the position of the oesophagus at the time of ablation.4
The proposed approach does not correctly express the oesophageal width, which is variable and can be quite broad4; with our method, the oesophagus is constructed at a fixed width based on the dimension of the oesophageal probe.  |
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[1] Pappone C, Oral H, Santinelli V, Vicedomini G, Lang CC, Manguso F, et al. Atrio-esophageal fistula as a complication of percutaneous transcatheter ablation of atrial fibrillation. Circulation 2004; 109: 2724–6.
[2] Mönnig G, Wessling J, Juergens KU, Milberg P, Ribbing M, Fischbach R, et al. Further evidence of a close anatomical relation between the oesophagus and pulmonary veins. Europace 2005; 7: 540–5.
[3] Kottkamp H, Piorkowski C, Tanner H, Kobza R, Dorszewski A, Schirdewahn P, et al. Topographic variability of the esophageal left atrial relation influencing ablation lines in patients with atrial fibrillation. J Cardiovasc Electrophysiol 2005; 16: 146–50.[CrossRef][Web of Science][Medline]
[4] Good E, Oral H, Lemola K, Han J, Tamirisa K, Igic P, et al. Movement of the esophagus during left atrial catheter ablation for atrial fibrillation. J Am Coll Cardiol 2005; 46: 2107–10.[Medline]
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