A system for ablation lesion depth assessment in myocardial tissue, the system comprising: a cryoablation device including: a balloon; one or more thermocouples coupled to the balloon; and a coolant injection element disposed within the balloon, the coolant injection element defining a plurality of ports; a coolant supply reservoir in fluid communication with the balloon, the plurality of ports of the coolant injection element being in fluid communication with the coolant supply reservoir and an energy generator in electrical communication with one or more electrodes on the balloon; and a control unit in communication with the one or more thermocouples, the control unit including a processor programmed to: receive temperature measurements from the one or more thermocouples; calculate a rate of change in temperature; and adjust the flow of coolant within in the balloon one of at a predetermined time from the time at which the processor detects an increase in the rate of change in temperature and when the processor detects an increase in the rate of change in temperature; wherein adjusting the flow of coolant includes one of: selectively delivering fluid to fewer than all of the plurality of ports of the fluid injection element; and redirecting the flow of fluid from the plurality of ports away from one or more thermocouples that detect an increased rate of change in temperature. a balloon; one or more thermocouples coupled to the balloon; and a coolant injection element disposed within the balloon, the coolant injection element defining a plurality of ports; a coolant supply reservoir in fluid communication with the balloon, the plurality of ports of the coolant injection element being in fluid communication with the coolant supply reservoir and an energy generator in electrical communication with one or more electrodes on the balloon; and a control unit in communication with the one or more thermocouples, the control unit including a processor programmed to: receive temperature measurements from the one or more thermocouples; calculate a rate of change in temperature; and adjust the flow of coolant within in the balloon one of at a predetermined time from the time at which the processor detects an increase in the rate of change in temperature and when the processor detects an increase in the rate of change in temperature; wherein adjusting the flow of coolant includes one of: selectively delivering fluid to fewer than all of the plurality of ports of the fluid injection element; and redirecting the flow of fluid from the plurality of ports away from one or more thermocouples that detect an increased rate of change in temperature. receive temperature measurements from the one or more thermocouples; calculate a rate of change in temperature; and adjust the flow of coolant within in the balloon one of at a predetermined time from the time at which the processor detects an increase in the rate of change in temperature and when the processor detects an increase in the rate of change in temperature; wherein adjusting the flow of coolant includes one of: selectively delivering fluid to fewer than all of the plurality of ports of the fluid injection element; and redirecting the flow of fluid from the plurality of ports away from one or more thermocouples that detect an increased rate of change in temperature. selectively delivering fluid to fewer than all of the plurality of ports of the fluid injection element; and redirecting the flow of fluid from the plurality of ports away from one or more thermocouples that detect an increased rate of change in temperature.