Letter to the Editor

Doll et al. [[1]] report on esophagus perforation after left atrial radiofrequency ablation. Due to a relatively increased incidence of esophagus perforation leading to death the use of radiofrequency ablation was abandoned.

In our institution we initiated the use of microwave ablation for the surgical therapy of atrial fibrillation in 1998. Based on our experience with 265 patients with endocardial microwave ablation and a follow-up of up to four years we have not seen any indications of device-related complications, in particular we saw no clinical evidence of esophageal injury or perforation [[2]].

In-hospital mortality is 3 %. So far, no device-related mortality occurred. A potential explanation for the reduced risk of injury with microwave ablation is based on its action mechanism. The action mechanism of microwave ablation is based on 2.45 GHz electromagnetic radiation. The electromagnetic radiation induces rotation of the hydrogen atoms in the water molecule. This results in a fixed and stable coagulation necrosis without surface overheating or carbonization of the tissue. This fact explains that microwave-induced lesions applied with a definite power range have a restricted and local ablation effect. The induced scar forms a natural barrier against the further extension of the lesion. An additional protective factor in this context is the low H₂O content in epicardial fat. This forms a natural barrier for the surrounding structures, in particular the esophagus, the vagus, and phrenic nerve.

Michael Knaut, MD Sems M. Tugtekin, MD Klaus Matschke, MD

References

• 1 Doll N, Borger M A, Fabricius A, Stephan S, Gummert J, Mohr F W, Hauss J, Kottkamp H, Hindricks G. Esophageal perforation during left atrial radiofrequency ablation: Is the risk too high?.  J Thorac Cardiovasc Surg. 2003;  125 836-842
• 2 Knaut M, Tugtekin S M, Spitzer S, Gulielmos V. Combined atrial fibrillation and mitral valve surgery using microwave technology.  Semin Thorac Cardiovasc Surg. 2002;  14 226-231