Complete heart block as the sole presentation of Lyme disease.

We report a case of Lyme myocarditis presenting solely as complete heart block in a previously healthy 32-year-old white man. Indium cardiac antimyosin scan showed diffuse uptake (2+, on a scale of 0 to 4+) during the acute phase of the illness. The electrocardiogram and the indium cardiac antimyosin scan were normal 6 weeks after completion of tetracycline and prednisone treatment. Lyme carditis should be considered in the differential diagnosis of complete heart block of unclear origins, even in patients presenting without other signs or symptoms suggestive of Lyme disease.