Can implantable cardiac electronic device infections be defined as 'early' or 'late' based on the cause of infection?

Implantable cardiac electronic device (ICED) infections are a major cause of morbidity and mortality. Understanding the pathogenesis of these infections is important in their prevention and management. We hypothesized that ICED infections could be classified as 'early' or 'late', based on differences in microbiological cause within or beyond 1 year of implantation, respectively. A comprehensive review of the literature was undertaken to test this hypothesis. Prosthetic valve endocarditis cases were included for comparison. Articles were included if the time from device implantation to infection, definite evidence of infection (pocket/bacteraemia/endocarditis) and a positive microbiological diagnosis were included. There were no statistically significant differences in microbiology to support a 1 year cut-off between early and late ICED infection. Staphylococcus aureus and coagulase-negative staphylococci were the predominant causes of ICED infection both within and beyond 1 year of ICED implantation. To further assess the microbiological causes of ICEDs and their implications for pathogenesis a large-scale multi-centre study is required.