A catheter sheath (10) comprises a tubular member (14) connected to a catheter handle (11), the tubular sheath including one or more electrical conductors (30) and one or more electrode rings (20) attached to the tip of the tubular member (14). The tubular member further includes at least one opening (28) that allows the one or more electrical conductor (30) to be electrically connected to the one or more electrode rings (20). The electrode ring (20) is slid over the tubular member (14) so as to cover the opening (28). The tubular member (4) and the electrode ring (20) are subjected to heat treatment by induction heating so that the material of the tubular member melts locally around the electrode ring (20) to form a seal between the tubular member (14) and the electrode ring (20).