Introduction & Aim of the work: Twenty five years have passed since the first implantedpermanent pacemaker (PM) back in 1982 at the Critical Care Department of CairoUniversity. A series of studies were conducted to register permanent PM implantationand follow up data starting from 1983 till the end of 2006, depending on the patients,admission files and the out-patient follow up records at the PM follow up clinic.During this lengthy follow up, several pacemakers implanted had to be replaced for avariety of reasons. The present study addresses the issue of re-implantation in a largereferral center, namely the Critcal Care Center at Cairo University over a quarter of acentury in terms of prevalence, etiology, and long term outcome.Patients and methods: Over the abovementioned period, 2699 permanent pacemakerswere implanted in 2088 patients. Patients studied were divided into two groups, group Icovered the period from 1983 to the end of 1993 (including 648 implants in 587patients), and group II covered the period from 1994 to the end of 2006 (including 2027implants in 1494 patients). The mean rate of implantation increased from 54/year ingroup I, to 160/year in group II. Permanent PM re-implantation showed progressiveincrease with time from 70 cases in group I, to 541 cases in group II (mean rate of reimplantationof 6/year in group I as compared to 42/year in group II). Results: Compared to the initial series of patients, the second group exhibited asignificantly lower rate of pocket infection and extrusion (11.4% in group II versus34.3% in group I respectively, p-value=0.00003), and lesser need for lead replacement(6.9% in group II versus 18.6% in group I, p-value=0.002). There was a higher rate ofnormal battery end of life in group II as compared to group I (61.4% versus 28.6%, pvalue=0.9), whereas, in both groups there was comparable prevalence of redoimplantationdue to the need for a new pacing mode or programmability (11.4% in groupI versus 13.2% in group II), and premature battery end of life (7.1% in group I versus 5%in group II). Two indications for re-do implantation were noticed in group II only;electronic component failure, and infective endocarditis on the pacemaker leadscomprising (1.2%, and 1% of re-implantations respectively). Conclusion: Out of 2700 permanent PM implanted by the Critical Care Pacing andElectrophysiology team over the last twenty five years, this study illustrates the parallelincrease in the overall permanent pacemakers new and re-implantation rates whichcontinue to reflect the increased referral to our center. The shifting of the mainindications of re-implantation from PM pocket infection and extrusion in group I, tonormal battery end of life in group II reflects the overall decline in the incidence ofcomplications owing to the increased experience and skill gained by the PM implantationteam overtime. Nevertheless, it is expected for the incidence of normal battery end oflife to increase with time, being a normal endpoint of PM implantation.The nearly fixed rate of re-implantation due to the need of a new pacing mode orprogrammability in both groups, (despite the marked increase in the implantation rate),illustrates the shift to more physiologic pacing modes matching the new indications ofpacing, which reflects a more experienced, and up-to-date decision making.Finally, the timely detection of the need of re-implantation reflects the efficiencyof follow up system adopted by our center.