Impedance drop determines ablation lesion volume at the same level of ablation index

Abstract

New parameters such as ablation index (AI) have been developed to create reliable ablation lesions. This study was performed to evaluate whether RF energy delivery with the same ablation index creates the similar ablation lesion volume. Ablation lesions were created in 5 pig hearts at ex-vivo state. Ablation was performed using an external-irrigation contact-force sensing catheter on the epicardial side of the left ventricle with 90-degree of angle. RF ablation time was adjusted for targeting AI 600 at 8 different conditions. Lesion volume created with 0–5g of contact force at 20 W was significantly lower than that of 11–20g at 40W despite of the same AI (125 ± 76.2 vs. 272 ± 49.5 mm3, P < 0.05). Quality of ablation lesion was variable in the condition of poor contact at low power for the ablation of ex-vivo swine left ventricle, and high-quality lesions could be expected when the impedance drop is satisfactory even though the same level of AI is applied during ablation.