[Relation between cavo-tricuspid isthmus anatomy studied by transesophageal echocardiography and the immediate outcome of radiofrequency ablation of common atrial flutter].

Radiofrequency ablation is the only curative treatment of common atrial flutter. The aim of the treatment is to create a line of bidirectional block at the level of the cavo-tricuspid isthmus. This objective can be achieved in the vast majority of the patients. However, it may difficult or even not possible to create an isthmus block. The anatomy of the right atrium is subject to important variations, especially at the isthmus level. We therefore tested the hypothesis that these anatomic variations might influence the immediate outcome of cavo-tricuspid isthmus ablation. The anatomy of cavo-tricuspid isthmus was studied by trans-oesophageal echocardiography. The shape of the isthmus (concave or not), the presence of diverticula and the degree of development of the Eustachian ridge were analysed. From these data, the cavo-tricuspid anatomy was classified as simple or complex. The immediate outcome of radiofrequency ablation was reviewed in 94 patients (mean age of 63 years) according to the anatomy, simple or complex. When the anatomy was classified as simple, the success rate of radiofrequency ablation was 95.6%; when the anatomy was complex, the success rate was 76.9% (overall success rate for the entire population equal to 90.4%). The length of the cavo-tricuspid isthmus did not influence the outcome of radiofrequency ablation. In summary, it appears that the anatomy of cavo-tricuspid isthmus seems to play a role in the immediate outcome of radiofrequency ablation of cavo-tricuspid isthmus.