A system and method for determining the optimum dose of cryotreatmentto an area of target tissue to achieve isolation based on the time to effect(TTE).The system may generally include a treatment device, a sensing device, and aprocessor programmed to calculate the optimum dose of cryotreatment, inseconds, based on TTE. The TTE may be based on electrical signals received bythe processor from the sensing device. The processor may be furtherprogrammed to automatically terminate a cryoablation procedure when theoptimum dose of cryotreatment has elapsed. The optimum dose of cryotreatmentmay be the time, in seconds, it takes to achieve isolation, which may be thetimeit takes for an area of tissue to reach approximately - 20 °C.
