An irrigation catheter assembly comprises an electrode sheath mount for mounting an electrode sheath. The mount has a laterally arranged aperture defined in it through which conductors for electrodes of the electrode sheath pass, in use. A connector, to which a source of irrigation fluid is connectable, is connected to a proximal end of the electrode sheath mount. The connector communicates with an interior of the mount so that, in use, fluid passes through the lumen of the electrode sheath to be delivered to a distal end of the electrode sheath.
