Surveys of pacing practice have shown a steady increase in pacemaker implantation rates in the past 15 years, despite no major changes in United States guidelines for permanent pacing. There are no data to explain why this is occurring. In this study, records were extracted from the National Hospital Discharge Survey to investigate this. There were 3 major findings. First, age-adjusted implantation rates increased progressively over the study period from 370 per million in 1990 to 612 per million in 2002. Second, it was found that the escalating implantation rate is attributable to increasing implantation for isolated sinus node dysfunction (SND). Implantation for SND increased significantly over the study period (by 102%), whereas implantation for all other indications did not. The increasing implantation for SND is due primarily to the increasing prevalence of SND, with a lesser increase in implantation rate relative to prevalence rate. The third major finding of this study is that there has been a progressive relative and absolute increase in the dual-chamber implantation rate. In 2002, 82.8% of all initial pacemaker implantations were dual-chamber devices. Furthermore, the National Hospital Discharge Survey data indicate that the major randomized pacing trials seem to have had no impact on pacing practice in the United States. In conclusion, age-adjusted implantation rates increased progressively over the study period. This escalating implantation rate is primarily attributable to increasing implantation for SND.