Lyme carditis in Europe

Lyme borreliosis is the most common tick-borne bacterial infection in Europe and is caused by members of the Borrelia burgdorferi sensu lato complex transmitted mainly by Ixodes ricinus. Although Lyme carditis represents an uncommon extracutaneous manifestation, it is clinically important because atrioventricular conduction disease can progress rapidly yet often resolves with timely antibiotic treatment, reducing avoidable permanent pacemaker implantation. This Mini Review synthesizes the European evidence on the microbiological, epidemiological, diagnostic, and surveillance dimensions of Lyme carditis. The European setting is distinct from North America because B. afzelii and B. garinii predominate, species-level attribution of cardiac disease is rarely available, and national Lyme borreliosis surveillance systems differ substantially in definitions, reporting routes, and captured manifestations. Available data suggest that Lyme carditis is rare among medically attended Lyme borreliosis cases but may be clinically relevant among patients with unexplained high-grade or fluctuating atrioventricular block in endemic regions. Diagnosis is complicated by absent tick-bite history or erythema migrans, early seronegativity, background seropositivity, older age at presentation, myocarditis or acute coronary syndrome-like phenotypes, and limited access to confirmatory tissue-based methods. We propose that European surveillance should incorporate cardiology-linked sentinel pathways, particularly before permanent pacemaker implantation, using standardized suspected, probable, and confirmed case categories supported by paired serology when feasible. Multicenter collaboration between cardiology, infectious diseases, microbiology, and public-health networks is needed to define incidence, optimize diagnostic algorithms, and clarify the contribution of European Borrelia species to cardiac involvement.