A system for deflecting a distal portion of a catheter into an at least partially hooped configuration, said system comprising: an elongated catheter body· defining a longitudinal axis and having a proximal portion and a distal portion, with the distal portion being formed with a lumen; a tube disposed in said lumen and having a wall formed with a plurality of slits (60, 62), said tube wall having an inner wall, said tube being transformable between a first, relaxed configuration wherein said tube is substantially straight shaped and a second, deflected configuration wherein said tube is at least partially hoop shaped, wherein the catheter body comprises a cryo-tip mounted at the distal end of the tube, and wherein the catheter body further comprises a tubular supply line (154, 156) for introducing a regulated flow of refrigerant from a refrigerant supply unit into at least one of the cryo-tip or the at least partially hooped configuration; a deflection wire having a distal end attached to said tube and a proximal end; a means (28, 90) operable on the proximal end of said deflection wire for moving said deflection wire axially to transform said tube from the first configuration to the second configuration and reshape the distal portion of the catheter; and a guiding means for maintaining said deflection wire along said inner wall during a movement of said deflection wire, the guiding means comprising a plurality of indentations; wherein each indentation is formed in said tube wall characterised in that, each indentation extends from one slit (60c, 60d) of the plurality of slits to an axially adjacent slit (60c, 60d) of the plurality of slits and each indentation forms a passageway for threading said deflection wire therethrough. an elongated catheter body· defining a longitudinal axis and having a proximal portion and a distal portion, with the distal portion being formed with a lumen; a tube disposed in said lumen and having a wall formed with a plurality of slits (60, 62), said tube wall having an inner wall, said tube being transformable between a first, relaxed configuration wherein said tube is substantially straight shaped and a second, deflected configuration wherein said tube is at least partially hoop shaped, wherein the catheter body comprises a cryo-tip mounted at the distal end of the tube, and wherein the catheter body further comprises a tubular supply line (154, 156) for introducing a regulated flow of refrigerant from a refrigerant supply unit into at least one of the cryo-tip or the at least partially hooped configuration; a deflection wire having a distal end attached to said tube and a proximal end; a means (28, 90) operable on the proximal end of said deflection wire for moving said deflection wire axially to transform said tube from the first configuration to the second configuration and reshape the distal portion of the catheter; and a guiding means for maintaining said deflection wire along said inner wall during a movement of said deflection wire, the guiding means comprising a plurality of indentations; wherein each indentation is formed in said tube wall characterised in that, each indentation extends from one slit (60c, 60d) of the plurality of slits to an axially adjacent slit (60c, 60d) of the plurality of slits and each indentation forms a passageway for threading said deflection wire therethrough.