Since the first pacemaker implantation in October 1958 by Senning and Elmqvist in Sweden, cardiac pacing for bradycardia has become a well-established therapy. The impressive growth of clinical experience and the rapid development of pacemaker devices have greatly contributed to this situation. The electrical therapy appears to be so easy that insertion of the lead and its connection to the pacemaker generator requires little effort, skill or insight. However, after implantation a patient's condition seldom remains stable, which requires a flexible pacing program to cover all new cardiac...