Catheter inversion to achieve complete isthmus block in patients with typical atrial flutter.

Endocardial catheter ablation is now considered as the therapy of first choice in highly symptomatic patients with recurrent atrial flutter. Despite of primary success rates between 90 and 100% complete isthmus block is sometimes hard to achieve. We present ablation results of 100 consecutive patients suffering from typical right atrial flutter. After a mean of 18 energy applications persistent bidirectional isthmus block could not be achieved in 16 patients and right atrial angiography was performed in all of them. In 9 patients a large Eustachian valve was detected and considered responsible for failure of endocardial catheter ablation of atrial flutter. Catheter manipulation targeting the anterior region of the Eustachian ridge was successful in all patients after looping the ablation catheter within the right atrium. With a mean of 3 additional RF applications, 6 of the 9 affected patients could be successfully ablated. Large Eustachian ridges are not a rare finding in patients undergoing ablation of typical right atrial flutter. Inversion of the ablation catheter within the right atrium is a simple technique providing excellent tissue contact of the ablation electrode with the anterior region of the Eustachian Ridge. Using this approach, the creation of bidirectional isthmus block is possible in the majority of the respective patients.