Impedance changes during intracardiac echocardiography-confirmed catheter contact in pulsed field ablation

PURPOSE: Pulsed field ablation (PFA) has become an established treatment modality for atrial fibrillation (AF). Adequate catheter-to-tissue contact is essential for effective energy delivery. However, impedance characteristics associated with directly visualized catheter contact during PFA have not been well characterized. We evaluated impedance changes measured by the Contact Index during intracardiac echocardiography (ICE)-confirmed catheter contact. METHODS: We retrospectively analyzed 30 consecutive patients who underwent index PFA for AF using a pentaspline catheter under a novel impedance measurement system (EnSite X, Abbott). Impedance changes in each pulmonary vein (PV) using both basket and flower configurations were measured. Catheter-to-tissue contact was confirmed by ICE positioned within the left atrium, and impedance changes associated with ICE-confirmed catheter contact were analyzed. RESULTS: A total of 2400 impedance measurements were analyzed. Median impedance changes ranged from 22% to 25% across pulmonary veins. Linear mixed-effects analysis demonstrated that both pulmonary vein location (P < 0.001) and catheter configuration (P < 0.001) were independently associated with impedance change, whereas no significant interaction was observed between pulmonary vein location and catheter configuration (P = 0.084). CONCLUSIONS: This study characterizes the distribution of impedance changes observed during ICE-confirmed catheter contact across different pulmonary veins and catheter configurations. These findings provide device-specific descriptive reference data for future prospective validation studies.