A method and system for cryotreatment of target tissue using a cryotreatment catheter through which a mapping catheter may be freely movable, even during activation of the cryotreatment element. The cryotreatment system may include a cryotreatment catheter, a mapping catheter slidably disposed within a lumen of the cryotreatment catheter, and one or more heating elements. The one or more heating elements may be disposed on the mapping catheter or within the lumen of the cryotreatment catheter. Activation of the one or more heating elements prevents the freezing of, or thaws, fluid within the lumen of the cryotreatment device when one or more cryotreatment elements are activated. The lack of frozen fluid within the lumen allows the mapping catheter to freely move within the cryotreatment catheter during a cryotreatment procedure, so that the mapping catheter may be positioned proximate the treatment site after initiation of cryotreatment.
