Lyme carditis is an uncommon disease entity with potential complications of the conductive system such as advanced atrioventricular nodal block. Here, we present an interesting case of a 56-year-old of Complete Heart Block, which revealed Lyme disease.

The importance of considering Lyme disease as an etiology of acute AV nodal conduction disorders.

A 56-year-old male patient with no significant past medical history, living in a rural environment, admitted in our intuition for symptomatic atrioventricular (AV) nodal block. At admission, physical examination discovered a tick bite (Fig. 1). The patient was monitored on telemetry. He did not require transcutaneous pacing. Lyme titers were sent and he was started on intravenous (IV) ceftriaxone for presumed Lyme carditis. His titers subsequently returned positive. His symptoms began to improve within one day of antibiotics.

Lyme disease is a systemic illness caused by the spirochete Borrelia burgdorferi. Typically there is an annular skin rash termed erythema migrans about 5–7cm in diameter at the site of the tick bite. Without timely diagnosis and effective treatment, there is widespread dissemination with neurologic, musculoskeletal, and cardiac involvement. Atrioventricular block can develop and quickly advance from first degree block to second degree. The average time from initial presentation to complete heart block is 2 weeks. The time for resolution of complete heart block, after treatment is initiated, is usually 6 days although it can vary from 1 day to 7 weeks assay (ELISA) test for Lyme antibodies is sensitive but not specific. The usual therapeutic regimens for Lyme carditis include ceftriaxone or doxycycline.

This case highlights the importance of taking a good travel history and emphasizes the importance of appropriate and timely therapy to prevent unnecessary interventions such as permanent pacemaker insertion.