Routine reduction of pulse generator voltage.

The porous-tip electrode has led to a significant advancement in pacing system technology. Experience with 38 patients with unipolar tined CPI porous endocardial electrodes, is reported. All patients had programmable pulse generators, CPI model number 531. The voltage in this pulse generator can be reduced from 5 to 2.5 volts. The pulse width threshold (PWT) at implantation was 0.06 ms at 5 volts in all 38 patients, and the PWT at implantation varied between 0.06 and 0.16 ms at 2.5 volts, with a mean PWT of 0.092 +/- 0.026 ms. The 38 patients were restudied six months later. The mean PWT measured at 5 volts was 0.076 +/- 0.018 ms. The PWT measured at 2.5 volts varied between 0.08 and 0.30 ms with a mean PWT of 0.178 +/- 0.067 ms. Twenty-three patients were restudied one year after lead implantation. The PWT measured at 2.5 volts varied between 0.08 and 0.30 ms with a mean PWT of 0.156 +/- 0.061 ms. All of the pulse generators were reprogrammed to 2.5 volts. This permitted a substantial prolongation of the pulse generator life (three to five years) with an improvement in the cost effectiveness of the pulse generator.