Purpose: Radiofrequency catheter ablation of typical atrial flutter can vary largely in duration from patient to patient. The purpose of this work was to determine optimal combination of ablation settings leading to the highest procedural efficacy.
Methods: Our retrospective multivariate analysis comprised 448 patients undergoing atrial flutter ablation with nonirrigated 8-mm catheters at 19 clinical centers. Four procedural variables were included in the prognostic model: preset maximum temperature, preset maximum power, catheter-tip material (gold vs. platinum-iridium), and ablation technique (maximum voltage-guided vs. conventional anatomical approach). Univariate and multivariate analyses were performed using the logistic regression (for acute ablation success) and Cox constant proportional hazard models (for cumulative ablation time).
Results: Significant multivariate predictors of acute ablation success were a higher preset maximum temperature (odds 1.083 per 1 °C, P < 0.05) and gold-tip catheter (odds 2.096, P < 0.05). Predictors of cumulative ablation time were the maximum voltage-guided ablation technique (hazard ratio 1.856, P < 0.001), higher preset maximum temperature (hazard ratio 1.039 per 1 °C, P < 0.001), and gold-tip catheter (hazard ratio 1.225, P < 0.05). The combination of optimal settings (70 °C, 70 W, gold-tip catheter, maximum voltage-guided technique) increased the acute success rate from 91.7 % (for the entire study cohort) to 100 %, and reduced median cumulative ablation time from 8.3 to 4.3 min, median total procedure duration from 76 to 55 min, and median fluoroscopy time from 14 to 7 min.
Conclusions: The combination of maximum voltage-guided gold-tip ablation at 70 °C and 70 W was associated with 100 % ablation success and minimal ablation times for nonirrigated ablation of atrial flutter.
Keywords: Atrial flutter; Gold-tip catheter; Maximum voltage-guided ablation; Predictors of ablation success rate; Preset maximum temperature; Radiofrequency catheter ablation.