Does temperature-controlled irrigated tip radiofrequency ablation enlarge lesion size compared to conventional ablation in porcine myocardium?
Temperature-controlled irrigated tip radiofrequency ablation with low target temperature and low infusion rate safely enlarges lesion size and reduces coagulum formation compared to conventional ablation in a porcine model.
INTRODUCTION: In patients with ventricular tachycardias due to structural heart disease, catheter ablation cures < 60% partly due to the limited lesion size after conventional radiofrequency ablation. Irrigated tip radiofrequency ablation using power control and high infusion rates enlarges lesion size, but has increased risk of cratering. The present study explores irrigated tip catheter ablation in temperature-controlled mode, target temperature 60 degrees C, using an irrigation rate of 1 mL/min, comparing this to conventional catheter technique, target temperature 80 degrees C. METHODS AND RESULTS: In vivo anesthetized pigs were ablated in the left ventricle. In vitro strips of porcine left ventricular myocardium were ablated in a tissue bath. Lesion volume was significantly larger after irrigated tip ablation both in vivo (544 +/- 218 vs 325 +/- 194 mm3, P < 0.01) and in vitro (286 +/- 113 vs 179 +/- 23 mm3, P < 0.001). The incidence of cratering was not significantly different between the two groups. In vivo, no coagulum formation on part of the catheter tip was seen after irrigated tip ablation as opposed to 52% of the applications with conventional ablation (P < 0.05). CONCLUSION: We conclude that temperature-controlled radiofrequency ablation with irrigated tip catheters using low target temperature and low infusion rate enlarges lesion size without increasing the incidence of cratering and reduces coagulum formation of the tip.
Petersen et al. (1998) studied this question.