Electroanatomic magnetic mapping during ablation of isthmus-dependent atrial flutter

Introduction: Although recent studies have demonstrated that the endpoint o f isthmus conduction block is superior to that of termination and subsequen t inability to induce atrial flutter (AFl), the optimal method for determin ing isthmus conduction block has not been determined. Electroanatomic magne tic mapping during coronary sinus (CS) pacing may provide a reliable endpoi nt for AFl ablation. Methods and Results: Catheter mapping and ablation was performed in 42 pati ents with isthmus-dependent AFl. The patients were divided into two groups, based on procedural endpoint: Group I (28 patients) - isthmus conduction b lock was determined based on multipolar catheter recordings and electroanat omic mapping, and Group II (14 patients) - isthmus conduction block was det ermined by electroanatomic mapping during CS pacing alone. In Group I, abla tion procedures were acutely successful in 25 of 28 patients (89 %). A 100 % concordance between the data presented by multipolar catheter recordings and electroanatomic mapping was noted in determining the presence or absenc e of isthmus conduction block. In Group II, ablation procedures were acutel y successful in 13 of 14 patients, 13 (93 %). After a mean of 16.3 +/- 3.7 months follow up, there was 1 atrial flutter recurrence in the 38 patients (2.6 %) with demonstrated isthmus block at the end of the procedure. Conclusions: Electroanatomic magnetic mapping during CS pacing is comparabl e to the multipolar catheter mapping technique for assessing isthmus conduc tion block as an endpoint for AFl ablation procedures.