Late infections of pacemaker units due to silicone rubber insulation boots.

Early in 1980, there was an increase at our hospital of late infections of pulse generator pockets not due to perforation. No source of contamination could be found; then, late in 1981, the infection rate decreased. The only change in procedure during this period was the introduction of silicone rubber boots around the pacemaker unit to prevent muscle pacing. The risk of late infection was 13.8%, when using a rubber boot, while otherwise it was only 2.6% (p less than 0.001). The infections were usually caused by ordinary skin bacteria. The authors believe that the infections were due to bacteria introduced inside the rubber boot, where they were practically out of reach of the ordinary defense mechanisms. The decrease in infection rate occurred after the introduction of silicone-coated pacemakers.