Is it possible to create a linear lesion with no local electrograms? Comparison between a three-dimensional mapping system and conventional fluoroscopy for cavotricuspid isthmus ablation of typical atrial flutter

OBJECTIVE: The aim of this prospective, randomised study was to evaluate the efficacy, safety and long-term outcomes of the complete disappearance of local electrograms along the linear lesion using the EnSite NavX three-dimensional mapping system as compared with conventional fluoroscopy for ablation of typical atrial flutter (AFL). METHODS: Seventy-three patients with spontaneous AFL episodes were randomised to undergo fluoroscopy-guided (group I, n=35) or EnSite NavX-guided (group II, n=38) ablation. When bidirectional isthmus block was achieved, the catheter was navigated back along the ablation line to assess the presence of local potentials along the lesion line. RESULTS: Bidirectional isthmus block was achieved in all patients. Mean total fluoroscopy time was 19.8 +/- 4.1 min in group I and 9.1 +/- 3.5 min in group II (P<0.001); mean fluoroscopy time required for radiofrequency ablation was 6.9 +/- 1.4 min in group I and 0.6 +/- 0.3 min in group II (P<0.001). During a follow-up of 16 +/- 9 months, three patients in group I (10%) experienced recurrence of AFL as opposed to none in group II (P<0.005). CONCLUSIONS: NavX technology allows accurate re-navigation of the lesion line to assess the presence of local potentials during an ablation procedure for typical AFL. Electroanatomic activation mapping can accurately identify gaps in the linear radiofrequency lesion with no AFL recurrence compared with 20% of recurrences after a standard procedure.