SURVIVAL OF IMPLANTABLE PACEMAKER LEADS

Early polyurethane leads were reported to have a high incidence of materials failure. In 1979 a six-center registry was begun. By October 31, 1989, 7,311 leads had been registered and lead longevity was calculated by individual manufacturer, cumulatively for all manufacturers and for individual leads. Each lead was registered at implant and at removal from service as having been removed for materials failure or for unrelated reasons. Calculations were made for 23 models and for a total of three manufacturers with more than 100 leads implanted. Four thousand seven hundred and sixty three leads (65.1%) were from Medtronic; 2,177 (29.8%) from Cordis; 297 (4.1%) from Intermedics; and 77 (1.0%) were from all others. The 10-year cumulative survival of Medtronic leads was 96.6 +/- 0.4%; for Cordis leads it was 99.9 +/- 0.1% and for Intermedics leads 97.7 +/- 0.9%. Three lead models registered over 100 units and had poorer survival at 5 years than the remainder of all manufacturers' experience. They were #6972 (n = 107) with 78.6 +/- 4.5%; #6991 U (n = 294) with 90.6 +/- 1.9%; and #4012 (n = 288) with 97.3 +/- 1.5%. Other possibly failed models did not achieve statistical significance. It can be anticipated that a lead which survives to the seventh year will have prolonged longevity as thereafter additional failures are uncommon.