Canine model of electrical conduction recurrence after radiofrequency catheter ablation constructed by CARTO3 and preliminary application evaluation of DOX-L.

Background: Radiofrequency catheter ablation (RFCA) is widely used to treat arrhythmias. However, for atrial fibrillation, the recurrence rate after RFCA is still high. The development of an animal model that mimics the recurrence of electrical conduction after ablation is essential before we can explore the mechanisms involved or develop new therapeutic strategies.

Methods: Eighteen beagles aged 12 to 24 months were randomly assigned to this study. RFCA ablation of the right atrial free wall was performed. Then, electrical block and conduction recovery in the ablation area were evaluated using voltage mapping and pacing tests assisted by CARTO3 system. Finally, liposome doxorubicin (DOX-L) was intravenously injected after ablation to investigate the effect of DOX-L on this animal model.

Results: The conduction block (CB) rates at 5 min after ablation were 16.7%, 83.3%, and 100%, corresponding to 30w, 35w, and 40w power, respectively. However, after 20 min, the rate of CB was 0%, 33.3%, and 75%; thus, the combined success rate of CB and conduction recurrence was 16.7%, 50%, and 25%, respectively. The optimal ablation parameter is 35 W for 20 s, based on the CB rate, REC rate. After 10 days of ablation, the residual conduction recurrence rate was as high as 83.3% in the RFCA alone group, whereas there was no recurrence with RFCA combined with DOX-L treatment.

Conclusions: The novel model accurately simulated the electrical conduction recurrence after cardiac radiofrequency ablation. RFCA combined with DOX-L treatment dramatically reduces the recurrence rate of electrical conduction after ablation.