Carditis de Lyme probable en candidatos a marcapasos con bloqueo auriculoventricular: resultados preliminares del...

To estimate the proportion of patients with newly diagnosed cardiac conduction disorders requiring pacemaker implantation who have serological findings consistent with probable Lyme carditis in endemic northern Serbia.

Adults presenting with new conduction disorders and scheduled for permanent pacing were enrolled and provided serum at baseline and 4‑week follow‑up. Anti‑Borrelia IgG was assessed using a two‑tier algorithm (ELISA screening, immunoblot confirmation). Probable Lyme carditis was defined as IgG seroconversion or stable/rising titers; no Lyme carditis as persistent seronegativity or declining titers.

Of 80 enrolled patients, 74 completed follow‑up (92.5%; mean age 71.6 years; 68.9% male). Third‑degree atrioventricular block was most frequent (56.8%). Probable Lyme carditis was identified in 8/74 (10.8%). Of 14 ELISA‑reactive/borderline patients, 6 were immunoblot‑negative (42.9%). Seropositive patients were older (76.3 vs 71.1 years); titers were higher in men at 4 weeks. IgG positivity was associated with suspected Lyme carditis (relative risk 6.8 at baseline; 16.2 at 4 weeks). No participant reported a recent tick bite or erythema migrans.

Approximately one in ten pacemaker candidates showed serological patterns compatible with probable Lyme carditis. Incorporating two‑tier, paired serology into evaluation of high‑grade conduction disorders in endemic settings may improve etiological diagnosis and inform management.