Remote magnetic catheter navigation for cavotricuspid isthmus ablation in patients with common-type atrial flutter.

BACKGROUND Conventional catheter ablation of cavotricuspid isthmus (CTI)-dependent atrial flutter is a widely applied standard therapy. Remote magnetic catheter navigation (RMN) may provide benefits for different ablation procedures, but its efficacy for CTI ablation has not been evaluated in a randomized, controlled trial. METHODS AND RESULTS Ninety patients undergoing de novo ablation of atrial flutter were randomly assigned to conventional manual (n=45) or RMN-guided (n=45) CTI ablation with an 8-mm-tip catheter. Complete bidirectional isthmus block was achieved in 84% (RMN) and 91% (conventional catheter ablation) of the cases (P=0.52). RMN was associated with shorter fluoroscopy time (median, 10.6 minutes; interquartile range [IQR], 7.6 to 19.9, versus 15.0 minutes; IQR, 11.5 to 23.1; P=0.043) but longer total radiofrequency application (17.1 minutes; IQR, 8.6 to 25, versus 7.5 minutes; IQR, 3.6 to 10.9; P<0.0001), ablation time (55 minutes; IQR, 28 to 76, versus 17 minutes; IQR, 7 to 31; P<0.0001), and procedure duration (114+/-35 versus 77+/-24 minutes, P<0.0001). Procedure duration in the RMN group did not decrease significantly with case experience. Long-term procedure success, defined as achievement of complete CTI block and freedom from atrial flutter recurrence during 6 months of follow-up, was lower in the RMN group (73% versus 89%, P=0.063). Right atrial angiography after ablation revealed no significant differences between groups in terms of right atrial diameter or CTI length, morphology, and angulation. Furthermore, none of these parameters was predictive for difficult (ablation time >20 minutes) or unsuccessful ablation. CONCLUSIONS RMN-guided CTI ablation is associated with reduced radiation exposure but prolonged ablation and procedure times as compared with conventional catheter navigation. Our findings suggest that ablation lesions produced with an RMN-guided 8-mm catheter are less effective irrespective of CTI anatomy. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00560872.