A catheter includes a handle, a catheter sheath having at least one conductor within a lumen of the catheter sheath, and a stylet received within the catheter sheath. The catheter sheath is fabricated by providing a tubular member, forming an aperture in a wall of the tubular member at a distal part of the tubular member and inserting a conductor into the lumen of the tubular member. An exposed distal end of the conductor is attached to an electrode, which is then mounted onto an external surface of the tubular member to cover the aperture. The tubular member is then treated by heat to seal the electrode.