Relationship Between Ablation Lesion Size Estimated by Ablation Index and Different Ablation Settings-an Ex Vivo Porcine Heart Study.

This study aimed to verify the reliability of ablation index (AI) for ablation lesion estimating with different settings for radiofrequency (RF) parameters: power, impedance, contact angles, irrigation rate, temperature of irrigation saline, and irrigation solution. RF ablations (N = 66) were performed on ex vivo porcine left ventricle submerged in 37 °C saline. The aforementioned ablation parameters were changed to measure whether the size of the ablation lesion was consistent at a fixed AI value of 500. The maximum lesion diameter (r = - 0.631, P = 0.028), depth (r = - 0.896, P < 0.001), and volume (r = - 0.745, P < 0.005) were significantly reduced with an increase of the impedance. The lesion depth (P < 0.05) and the lesion volume (P < 0.05) were significantly larger with glucose irrigation than saline irrigation. In conclusion, at a fixed AI value, impedance and irrigation solution have impact on the ablation lesions, which could affect the accuracy of AI formula to estimate ablation lesion size. Graphical abstract.