EACH YEAR in the United States 25,000 to 30,000 cases of heart block associated with Stokes-Adams seizures and chronic congestive heart failure are recorded. The development of implantable cardiac stimulators for the treatment of this problem began over 15 years ago and the first successful clinical application was reported in 1960.1 Several units are now commercially available and are being improved. However, a marked discrepancy still exists between industrial data on component durability and clinical experience. In a recent representative series, a total of 53 pacemakers and 22 reparative operations were required by 37 patients. Failures occurred from four months to 2½ years after implantation.2 The need for improvement is evident and a technique for the nonoperative repair of internal cardiac pacemakers will therefore be presented. Instruments and Use Figure 1 illustrates the design of the reed switch used in the repair procedures. The nitrogen gas filled glass