A modular handle assembly for supporting and controlling a steerable catheterhaving at least one deflection wire includes a handle portion which extendsalong an axis forbeing secured about a portion of the steerable catheter. The modular handleassembly includesat least one barrel that is rotatably connected to the handle portion forrotation about said axisand at least one actuation screw shaft that is disposed within said handleportion and whichextends through the barrel for connection with the deflection wire of thesteerable catheter. Atleast one pinion gear is disposed radially between the actuation screw shaftand the barrel and isthreadedly interconnected with the actuation screw shaft and the barrel fortranslating rotationalmovement of the barrel about the axis into axial movement of the actuationscrew shaft toprovide for movement of the deflection wire to curl the steerable catheter.
