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The limited success rate of radiofrequency catheter ablation in patients with ventricular tachycardias related to structural heart disease may be increased by enlarging the lesion size. Irrigated tip catheter ablation is a new method for enlarging the size of the lesion. It was introduced in the power-controlled mode with high power and high infusion rate, and is associated with an increased risk of crater formation, which is related to high tissue temperatures. The present study explored the tissue temperatures during temperature-controlled irrigated tip ablation, comparing it with standard temperature-controlled ablation and power-controlled irrigated tip ablation. In vitro strips of porcine left ventricular myocardium were ablated. Temperature-controlled irrigated tip ablation at target temperatures 60 degrees C, 70 degrees C, and 80 degrees C with infusion of 1 mL saline/min were compared with standard temperature-controlled ablation at 70 degrees C and power-controlled irrigated tip ablation at 40 W, and infusion of 20 mL/min. Lesion size and tissue temperatures were significantly higher during all modes of irrigated tip ablation compared with standard temperature-controlled ablation (P 100 degrees C. We conclude that irrigated tip catheter ablation increases lesion size and tissue temperatures compared with standard ablation in the temperature-controlled mode at the same or higher target temperatures and in the power-controlled mode. Furthermore, tissue temperature and delivered power are the best indicators of lesion volume during temperature-controlled ablation.
Petersen et al. (Sat,) studied this question.