“Largest Amplitude Ablation” is the Optimal Approach for Typical Atrial Flutter Ablation: A Subanalysis from the AURUM 8 Study

Abstract

The recently proposed "maximum voltage-guided" (MVG) technique for radiofrequency catheter ablation of atrial flutter targets high-voltage electrograms along cavotricuspid isthmus (CTI) to ablate the functionally important anatomic muscle bundles alone, without drawing a complete anatomic line across the CTI. This innovative approach may shorten ablation time and procedure duration. Within the multicenter AURUM 8 study, which compared 8-mm gold- and Pt-Ir-tip catheters in atrial flutter ablation, we made a post hoc comparison of procedural data from 72 patients treated with MVG technique with data from 281 patients undergoing anatomic CTI ablation (unmatched) and with data from 72 patients selected from among those 281 patients such that they were matched with the MVG group with respect to selected baseline parameters and catheter type (matched). The MVG technique markedly reduced (P < 0.001) ablation time (mean 6.9 minutes vs 10.9/9.7 minutes [unmatched/matched]), number of lesions (8.3 vs 13.7/12.9), fluoroscopy time (9.5 minutes vs 20.6/17.9 minutes), procedure duration (59 minutes vs 93/86 minutes), and energy delivered (19 kJ vs 34/30 kJ) compared with anatomic CTI ablation. The incidence of charring was higher for MVG than for anatomic ablation technique (31.9% vs 18.5/15.3%, P < 0.05), where Pt-Ir tip catheters were 6-fold more susceptible to charring than gold-tip catheters (P < 0.001), likely because of a lower thermal conductivity of the Pt-Ir material. The acute success rate was slightly better for MVG than for anatomic ablation technique (97.2% vs 92.2/91.7%, P = n.s.). Major procedural parameters are remarkably improved with MVG technique. Gold-tip catheters are substantially less susceptible to charring and may therefore be preferred over Pt-Ir-tip catheters for MVG ablation technique.