A device and system for providing mapping and treatment capabilities without increasing stiffness of the device. An embodiment of a device may include a flexible elongate body and at least one mapping element on the distal portion of the elongate body. Each mapping element may be an area of thermally conductive material, such as metallic nanoparticles, that is embedded within, integrated with, or deposited on the elongate body. The flexibility of the areas of thermally conductive material is at least substantially the same as that of the elongate body so the device may include many electrodes without compromising flexibility and maneuverability of the device. Alternatively, the device may include a treatment element coupled to the elongate body, such as a balloon. The mapping elements may be embedded within, integrated with, or deposited on the balloon and may have at least substantially the same flexibility as that of the balloon.