System for controlling the energy delivered to a patient for ablation

摘要

A power control system and method controls a power generator to vary the duty cycle of a power output provided to a delivery instrument for delivering that power to a site in a patient for ablation. The peak power can be raised and the duty cycle lowered to result in deeper lesions. However, the effective power is controlled so that it does not exceed a predetermined level. A power output having a higher peak power for producing deeper lesions can be obtained by using a lower duty cycle having a longer "off" period in order to deliver more power to the ablation site without overheating the delivery instrument. The maximum peak power that may be selected is determined in accordance with the structural limitations of the delivery instrument. The temperature of the delivery instrument is monitored, and the duty cycle is lowered when the temperature exceeds a predetermined maximum limit. After the instrument has cooled sufficiently, the duty cycle is then increased to its previous level.