Described embodiments include an apparatus that includes a catheter and a tip electrode, at a distal end of the catheter, shaped to define a plurality of fluid apertures. A structure, within the tip electrode, is configured such that fluid passed distally through a lumen of the catheter flows in a longitudinal direction through a space between the structure and an inner surface of the tip electrode, prior to exiting through the fluid apertures. Other embodiments are also described.
