Lyme borreliosis, caused by the tick-borne spirochete Borrelia burgdorferi, has been found to cause a variety of clinical syndromes including cardiomyopathy, dermatopathy, neuropathy, and arthropathy. Lyme carditis was originally described as a mild self-limited carditis, primarily involving the conduction system. However, recent reports suggest that cardiac involvement may be more serious than previously suspected, and may cause heart failure and probably congestive cardiomyopathy.