Abstract: A heart pacemaker system has an electrode line with a proximal end which is introduced into a connector of the pacemaker housing, and a distal end having an electrode head attachable to the heart of a user. One or more of the distal or proximal ends of the electrode line, the connector, or a region of the electrode line are provided with a component consisting of shape-memory metal. These components have a first shape at temperatures different from body temperature, and assume a second shape when at body temperature. The shape-memory metal component, if disposed at the proximal end of the electrode line or at the connector, is arrnaged to provide a firm mechanical and electrical connection of the electrode line with the pacemaker housing upon the change of shape of the component.