Pacemaker infections. A clinical study with special reference to prophylactic use of some isoxazolyl penicillins.

Infection is a major complication of pacemaker treatment. Antibiotic prophylaxis has been used in association with pacemaker surgery with conflicting results, and conclusive prospective trials are lacking. This investigation indicated that systemic antibiotic prophylaxis was of benefit when infections occurred frequently. The effect of local antibiotic prophylaxis was comparable with that of systemic prophylaxis at generator replacements. No serious adverse effects of the prophylaxis were noted. However, with modern surgical methods and hygienic principles, antibiotic prophylaxis did not seem to be necessary at implantation of new cardiac pacemakers. Once infection had developed it was difficult to eradicate and serious complications sometimes occurred. Most infections commenced in the pacemaker pocket. A few cases were cured by antibiotic treatment alone but, particularly if the infection spread along the electrode, surgery was strongly needed and in the presence of endocarditis and/or septicemia all foreign material should be removed if possible. The most common causal microorganisms of pacemaker infections were Staphylococcus aureus and Staphylococcus epidermidis. Routinely performed pre-, per- and postoperative cultures were of no prognostic value. Persistent use of antibiotics could select for methicillin-resistant coagulase-negative staphylococci, therefore bacteriological monitoring of wound infections was considered important. The dosage schedules used for cloxacillin and flucloxacillin gave satisfactory serum concentrations peroperatively. Local treatment with cloxacillin in the pacemaker pocket peroperatively gave adequate concentrations in tissue fluid from the pocket 24 h after the operation, as did systemic administration of flucloxacillin. The pharmacokinetics of flucloxacillin in these elderly patients differed in some respects from that found in healthy volunteers. Plasma elimination half-life was almost twice as long. Despite the high degree of plasma protein binding, flucloxacillin appeared to pass rapidly and efficiently to extravascular compartments, such as a pacemaker pocket.