Lyme disease is a multisystem disease caused by infection with Borrelia burgdorferi. Cardiac involvement occurs during the early disseminated phase of the disease, usually within weeks to a few months after the onset of infection [1,2]. The most common clinical feature of Lyme carditis is atrioventricular (AV) conduction block related to dysfunction of the conduction system, but may also include decreased cardiac contractility due to myopericarditis.
The epidemiology, clinical manifestations, diagnosis, treatment, and prognosis of Lyme carditis will be reviewed here. Other manifestations of Lyme disease are discussed separately. (See "Epidemiology of Lyme disease" and "Clinical manifestations of Lyme disease in adults" and "Lyme disease: Clinical manifestations in children" and "Nervous system Lyme disease" and "Musculoskeletal manifestations of Lyme disease" and "Treatment of Lyme disease".)
The incidence of Lyme carditis has varied in different reports:
- Carditis has been reported in approximately 4 to 10 percent in surveillance studies of untreated adults with Lyme disease in the United States [1,3-5]. However, at least some of these studies included palpitations as an indicator of carditis . In the largest surveillance study of 5016 patients in the United States with Lyme disease, 875 had sufficient data on possible cardiac manifestations . Cardiac manifestations were present in 84 patients (10 percent). Palpitations, which could be a nonspecific finding, were the most common manifestation, whereas more objective features of carditis (conduction defects, myocarditis, and/or pericarditis) occurred in 3 percent of patients, or less if some of these patients had more than one manifestation.
- In Europe, carditis has been reported as a complication of Lyme disease in approximately 0.3 to 4.0 percent of untreated adults . Some authors have suggested that the incidence of carditis may be lower in Europe compared with the United States. However, given the possible overestimate of clinically significant cardiac manifestations in the United States described above , the incidence of Lyme carditis may be similar in both regions.
The rate of carditis in children is not known. In a prospective study that included 14 children with proven Lyme disease in the United States who had electrocardiograms, two patients had first degree atrioventricular block, one had left axis deviation, and one had ventricular ectopy .