Change in the local impedance and electrograms recorded by a micro‐electrode tip catheter during initial atrial fibrillation ablation

Background A novel measurement of the local impedance (LI) and electrograms recorded from micro‐electrodes on catheter tip has been developed. However, the data during pulmonary vein (PV) ablation is not sufficient. We aimed to investigate the utility of this measurement during initial atrial fibrillation (AF) ablation. Methods We investigated 111 representative radiofrequency applications in 7 AF patients without a history of prior ablation (6 males, age 68 [65‐72] years, 2 persistent AF). The ablation strategy was PV isolation for paroxysmal AF and single ring box isolation for persistent AF, using MiFi catheter. The correlation of the generator impedance (GI) drop and LI drop after radiofrequency applications and the predictive value of the initial LI elevation before radiofrequency applications for LI drop were analyzed. Also, the LI and GI drop were investigated according to the location of RF applications. Results The LI drop was higher than GI drop (23.7 [16.4‐35.7] and 9.0 [6.0‐12.0]; P