Output programmability and reduction of secondary intervention after pacemaker implantation

Abstract

Six hundred one new or initial pacemaker implants between Jan. 1, 1972, and Dec. 31, 1979, consisted of 289 output-programmable pulse generators and 312 fixed-output generators. Standard leads were used in all instances. Of the 289 output-programmable pulse generators, 4.5% (13) required revision for failure to capture the heart in the postimplant period; of the 312 fixed-output units. 9.6% (30) required revision (p = 0.015). In 41 patients the early threshold was above standard output (5 V. 10 mamp, 0.5 msec), and in six of them approximately 6 months were required to return to stable threshold levels below standard output. In the remainder, threshold rose above standard output and was managed by increased output of the output-programmable pulse generators, either briefly or permanently. We conclude that output programmability allows reduction in secondary intervention after implantation and that threshold evolution may occupy a period as long as 6 months.