Early disseminated Lyme disease: cardiac manifestations.

The cardiac features of Lyme disease usually occur within weeks to months of the infecting tick bite; the result may be disruption of the conduction system, leading to heart block and muscle dysfunction, causing a mild myopericarditis. Lyme carditis is usually mild, although permanent heart block and a few fatalities claimed to be due to Lyme carditis have been reported, the latter usually with poor documentation. In general, Lyme carditis is treatable and curable with antibiotic regimens in current use. Recent reports have suggested that Lyme disease may be a cause of chronic congestive cardiomyopathy. Lyme carditis should be considered in the proper clinical setting with appropriate use of diagnostic tests, recalling that patients with carditis early in Lyme disease may be seronegative and that all patients who are seropositive do not necessarily have Lyme disease.