A system for predicting lesion quality, the system comprising: a treatment device, the treatment device including at least one temperature sensor and a shaft, the shaft including an occlusion element, a central lumen and at least one opening in fluid communication with the central lumen; and a console including: a source of cooled saline in fluid communication with the central lumen and the at least one opening, the cooled saline being injected from the treatment device; an energy generator in electrical communication with the treatment device; and a processor, the at least one temperature sensor being configured to send temperature data to the processor, the processor being programmed to receive temperature data recorded by the at least one temperature sensor and to calculate a rate of temperature increase in the cooled saline after injection from the treatment device over a time period of between approximately 2 seconds and approximately 15 seconds, the processor being further programmed to determine a pulmonary vein occlusion status based at least in part on the rate of temperature increase and to predict a lesion quality, the lesion quality being based at least in part on the pulmonary vein occlusion status. a treatment device, the treatment device including at least one temperature sensor and a shaft, the shaft including an occlusion element, a central lumen and at least one opening in fluid communication with the central lumen; and a console including: a source of cooled saline in fluid communication with the central lumen and the at least one opening, the cooled saline being injected from the treatment device; an energy generator in electrical communication with the treatment device; and a processor, the at least one temperature sensor being configured to send temperature data to the processor, the processor being programmed to receive temperature data recorded by the at least one temperature sensor and to calculate a rate of temperature increase in the cooled saline after injection from the treatment device over a time period of between approximately 2 seconds and approximately 15 seconds, the processor being further programmed to determine a pulmonary vein occlusion status based at least in part on the rate of temperature increase and to predict a lesion quality, the lesion quality being based at least in part on the pulmonary vein occlusion status. a source of cooled saline in fluid communication with the central lumen and the at least one opening, the cooled saline being injected from the treatment device; an energy generator in electrical communication with the treatment device; and a processor, the at least one temperature sensor being configured to send temperature data to the processor, the processor being programmed to receive temperature data recorded by the at least one temperature sensor and to calculate a rate of temperature increase in the cooled saline after injection from the treatment device over a time period of between approximately 2 seconds and approximately 15 seconds, the processor being further programmed to determine a pulmonary vein occlusion status based at least in part on the rate of temperature increase and to predict a lesion quality, the lesion quality being based at least in part on the pulmonary vein occlusion status.