TEMPERATURE-CONTROLLED IRRIGATED TIP RADIOFREQUENCY CATHETER ABLATION- COMPARISON OF IN-VIVO AND IN-VITRO LESION DIMENSIONS FOR STANDARD CATHETER AND IRRIGATED TIP CATHETER WITH MINIMAL INFUSION RATE

Introduction: In patients with ventricular tachycardias due to structu ral heart disease, catheter ablation cures < 60% partly due to the lim ited lesion size after conventional radiofrequency ablation, Irrigated tip radiofrequency ablation using power control and high infusion rat es enlarges lesion size, but has increased risk of cratering, The pres ent study explores irrigated tip catheter ablation in temperature-cont rolled mode, target temperature 60 degrees C, using an irrigation rate of 1 mL/min, comparing this to conventional catheter technique, targe t temperature 80 degrees C. Methods and Results: In vivo anesthetized pigs were ablated in the left ventricle, In vitro strips of porcine le ft ventricular myocardium were ablated in a tissue bath. Lesion volume was significantly larger after irrigated tip ablation both in vivo (5 44 +/- 218 vs 325 +/- 194 mm(3), P < 0.01) and in vitro (286 +/- 113 v s 179 +/- 23 mm(3), P < 0.001), The incidence of cratering was not sig nificantly different between the two groups. In vivo, no coagulum form ation on part of the catheter tip was seen after irrigated tip ablatio n as opposed to 52% of the applications with conventional ablation (P < 0.05). Conclusion: We conclude that temperature-controlled radiofreq uency ablation with irrigated tip catheters using low target temperatu re and low infusion rate enlarges lesion size without increasing the i ncidence of cratering and reduces coagulum formation of the tip.