A modular catheter comprises a tubular sheath module having one or more electrodes attached to the distal end of the tubular sheath and an elongate shape-imparting mechanism module. The shape-imparting mechanism module is removably received within a lumen defined by the tubular member. The tubular sheath module and the shape-imparting mechanism module are releasably connectable to a handle module. The handle comprises a plurality of wall members defining a cavity housing one or more modules releasably connected to the handle and accessible by at least partially separating the wall members. The tubular sheath, the shape-imparting mechanism module and the handle are replaceable independently and can be sterilized for subsequent use.