Lyme disease is a vector-borne illness that can affect numerous organ systems during the early disseminated phase, including the heart. The
clinical course of Lyme
carditis is usually benign with most patients recovering completely. In rare instances, death from Lyme
carditis has been reported. The cardinal manifestation of Lyme
carditis is conduction system disease, which generally is self-limited.
Heart block occurs usually at the level of the atrioventricular node but often is unresponsive to
atropine sulfate. Temporary pacing may be necessary in more than 30% of patients, but permanent
heart block rarely develops. Myocardial and pericardial involvement can occur but generally is mild and self-limited. Diagnosis is made by associating the clinical and historical features of borreliosis, such as previous
tick bite, EM, or neurologic involvement, with electrocardiographic abnormalities and symptoms such as
chest pain, palpitations,
syncope, and
dyspnea. Serologic studies and endomyocardial biopsy can support the diagnosis in the correct clinical setting, and MR imaging, echocardiography, and
gallium scanning have utility in selected circumstances. No treatment has been shown clearly to attenuate or prevent the development of Lyme
carditis, but mild
carditis generally is treated with oral
antibiotics and severe
carditis with intravenous
antibiotics in an effort to eradicate the
infection and prevent late complications of
Lyme disease. There is conflicting evidence regarding the role that B. burgdorferi plays in the development and progression of chronic
congestive heart failure. Because of the significant false-positive ELISA rate in this population and the unclear benefit of
antibiotic therapy, confirmatory Western blot analysis is recommended. Routine
therapy and screening of patients with
idiopathic dilated cardiomyopathy is of limited utility and should be reserved for patients with clear history of antecedent
Lyme disease or
tick bite.