ABSTRACT
The initial results acquired from testing of a new activated pyrocarbon electrode for cardiac pacing are presented. In vitro testing has shown energy efficiency to be higher than for platinum electrodes. Histologic examination of implanted leads in animals has demonstrated a less significant tissue reaction at the tip. Finally, in a clinical trial of 121 patients with these leads, strength-duration curves have low rheobase values. Chronic thresholds are often consistently low. These reports suggest very satisfactory results with this pyrolytic carbon electrode.
Subject(s)
Biocompatible Materials/therapeutic use , Carbon/therapeutic use , Pacemaker, Artificial , Animals , Biocompatible Materials/adverse effects , Carbon/adverse effects , Dogs , Electric Stimulation , Electrodes, Implanted , Endocardium/pathology , Humans , Platinum/adverse effects , Platinum/therapeutic use , Sheep , Sodium Chloride/therapeutic useABSTRACT
Platinum electrodes for cardiac stimulation having a surface porosity in the range of 40 micrometers have been prepared with a sintering process. These electrodes showed excellent in vitro characteristics (low polarization and sensing impedance). Animal testing proved good tissue acceptance and clinical trials in 31 patients gave the following results: threshold at implant 0,375 microJ (SD: 0.174 microJ), chronic threshold 1.15 microJ (SD: 1.05 microJ). The longest observation period was 7 months and the mean observation period was 17.1 weeks. These results indicate that this type of electrode allows safe stimulation of the heart with low energy pulses; in particular a reliable safety margin could be obtained with pulses having the amplitude of the existing lithium batteries, avoiding the need for a voltage doubler. This would improve the battery utilization and the pulse generator longevity.
