Prospective randomized comparison of durability of bidirectional conduction block in the cavotricuspid isthmus in patients after ablation of common atrial flutter using cryothermy and radiofrequency energy: The CRYOTIP study

BackgroundRecent studies have shown that cryoablation and radiofrequency (RF) ablation are comparable with regard to success rates and safety in the treatment of common atrial flutter (AFL). Long-term success requires persistence of bidirectional conduction block (BCB) in the inferior cavotricuspid isthmus (CTI).ObjectiveThe purpose of this study was to determine the persistence of BCB in a prospective randomized multicenter trial of the two ablation techniques.MethodsA total of 191 patients were randomized to RF ablation or cryoablation of the CTI using an 8-mm-tip catheter. In all patients, BCB was defined as the ablation end-point. Primary end-point of the study was nonpersistence of achieved BCB and/or ECG-documented relapse of common AFL within 3-month follow-up.ResultsAcute success rates were 91% (83/91) in the RF group and 89% (80/90) in the cryoablation group (P = NS). Invasive follow-up after 3 months with repeated electrophysiologic study was available for 60 patients in the RF group and 64 patients in the cryoablation group. Persistent BCB could be confirmed in 85% of the RF group versus 65.6% of the cryoablation group. The primary end-point was achieved in 15% of the RF group and 34.4% of the cryoablation group (P = .014). As a secondary end-point, pain perception during ablation was significant lower in the cryoablation group (P <.001).ConclusionPersistence of BCB in patients treated with cryoablation reinvestigated after 3 months is inferior to that patients treated with RF ablation, as evidenced by the higher recurrence rate of common AFL seen in this study.