TEMPERATURE-CONTROLLED RF ABLATION IN CANINE VENTRICLE AND CORONARY SINUS USING 7-FR OR 5-FR ABLATION ELECTRODES

The safety and lesion volume of temperature controlled radiofrequency ablation (TCRFA) in the right ventricle (RV), left ventricle (LV), and coronary sinus (CS) comparing long 5 Fr to standard tip electrodes ha ve not been previously reported. In 10 canines, TCRFA was delivered at a 70.C set point for 30 seconds. Lateral and septal RV lesions were m ade with either a 5 Fr/5 mm or 7 Fr/4 mm tip. Lateral and septal LV le sions were made with either a 5 Fr/7 mm or 7 Fr/4 mm tip. Proximal and distal CS lesions were made with either a 7 Fr/4 mm, 5 Fr/5 mm or 5 F r/7 mm tip. Gross and histologic examination of the lesions was comple ted. Lesion size, tip temperature and power required are related to el ectrode surface area (SA) when ablating in the RV, LV or CS. 5 Fr/7 mm lips (SA = 36 mm(2)) tended to create larger lesions than 7 Fr/4 mm t ips (SA = 29 mm(2)) in the LV. 7 Fr4 mm tips tended to create larger l esions than 5 Fr/5 mm tips (SA = 26 mm(2)) in the RV. 7 Fr/4 mm LV les ions exceeded 7 Fr/4 mm RV lesions due to thicker LV walls. In the CS, 5 Fr/7 mm tips tended to create the largest lesions. In the RV, LV an d CS, tips with larger SA tended to have lower temperatures and requir e higher power. No high temperature or high impedance shutdowns were o bserved. In conclusion varying 5 Fr tip length can safely produce larg er or smaller lesions compared to those created with 7 Fr/4 mm tips.