J Thorac Cardiovasc Surg 2006;132:213-214
© 2006 The American Association for Thoracic Surgery
Reply to the Editor
Heike Aupperle, MD,
Nicolas Doll, MD
Heart Center Leipzig, University of Leipzig, Leipzig, Germany
Reply to the Editor:
We have reviewed the letter to the editor from Hornero and Berjano, who presented some comments and questions on our paper.
1
The first points on which they remarked were the definite distance between the esophagus and the atrium in the sheep model, as well as the thickness of the ovine left atrial wall. The model we used has been established and controlled by magnetic resonance imaging.
1
The distance between the esophagus and the atrium (4 mm) showed minimal individual differences (LIT2) and is not responsible for the differences between the groups. As described by Aupperle et al.,
2
the thickness of the atrial wall in the investigated sheep was 3.2+/–0.8 mm,
2
and variations of the thickniess did not correlate with the effectiveness of atrial ablation.
2,4,5
Temperature measurement in the esophageal lumen was controlled by palpation to confirm the correct position of the tube, which had several measurement points.
1
The inner mucosal layer was not affected in any case, which makes an incorrect measurement more unlikely but confirms the thesis that the temperature inside the esophageal lumen did not increase. Furthermore, we discussed that the animals' body temperature was decreased (32°C) by the application of endocardial techniques,
1
probably leading to a protection of the tissue.
Clinical reports of human patients described cases of esophageal lesions after atrial ablation after unipolar radiofrequency.
3
These clinical data corresponded well to our findings, that the risk of esophageal lesions in the sheep model was highest after applictaion of endocardial unipolar radiofrequency. The results of the histomorphologic investigations of the ablated hearts in that study
2
showed that endocardial unipolar radiofrequency and cryobalation resulted in sharply demarcated transmural necrosis of the atrial tissue, which did not lead to severe thrombosis. In contrast, laser and microwave energy induced wide non-demarcated transmural lesions and severe thrombosis.
We agree that hypothermically and hyperthermically induced lesions depend on different pathomechanisms,
4
however, in our experiment involving acute lesions, we only could speculate about variations in subsequent wound healing processes. We think that the esophageal lesions, although small, reflect the early stages and the pathogenesis of fatal human cases.
 |
References
|
|---|
- Aupperle H, Doll N, Walther T, Kornherr P, Ullmann C, Schoon HA. Ablation of atrial fibriollation and esophageal injury. effects of energy source and ablation technique. J Thorac Cardiovasc Surg 2005;130:1549-1554.[Abstract/Free Full Text]
- Aupperle H, Doll N, Walther T, Ullman C, Schoon HA, Mohr FW. Histological findings induced by different energy sources in atrial ablation in sheep. Interactive Cardiovasc Thorac Surg 2005;4:450-455.[Abstract/Free Full Text]
- Doll N, Borger M, Fabricius A, Stephan S, Gummert J, Hauss J, Kottkamp H, et al. Esophageal perforation during left atrial radiofrequency ablation. is the risk too high?. J Thorac Cardiovasc Surg 2003;125:836-842.[Abstract/Free Full Text]
- Santiago T, Melo J, Gouveia RH, Martins AP. Intra-atrial temperatures in radiofrequency endocardial ablation. histologic evaluation of lesions. Ann Thorac Surg 2003;75:1495-1501.[Abstract/Free Full Text]
- Santiago T, Melo J, Gouveia RH, Neves J. Epicardial radiofrequency applications in vitro and in vivo studies on human atrial myocardium. Eur J Cardiothorac Surg 2003;24:481-486.[Abstract/Free Full Text]
Related Article
-
Atrial ablation and esophageal injury: Comments on an experimental study
- Fernando Hornero and Enrique J. Berjano
J. Thorac. Cardiovasc. Surg. 2006 132: 212-213.
[Extract]
[Full Text]
[PDF]
Top
References