Long-term threshold stability with porous tip electrodes.

Abstract

Experience with 163 unipolar tined porous endocardial electrodes is reported. One patient required repositioning of the electrode because of exit block. There were no other complications in the entire series of patients. All of the patients had low chronic stimulation thresholds. The mean pulse width 24 hours after implantation was 0.0534 +/- 0.0128 ms. Seventy-four patients were restudied six months after implantation. The mean pulse width threshold was then 0.07432 +/- 0.0775 ms. Fifty-four patients were evaluated one year after lead implantation. The mean pulse width threshold was then 0.0611 +/- 0.0230 ms. The pulse generator was reprogrammed to a lower pulse width in all of the patients. This permitted a substantial prolongation of the pulse generator life. The cost effectiveness of the pulse generator was also greatly improved by pacing with reduced pulse widths. In an additional 16 patients, the voltage amplitude was reduced from 5.0 volts to 2.5 volts. This permitted an even greater increase in the pulse generator longevity.