Lyme Endocarditis

Background: Valvular involvement as a manifestation of Lyme carditis is rare. The first case describing a possible association between Lyme disease and cardiac valvular disease in the United States was published in 1993. Since that time there have been 2 cases of Lyme endocarditis confirmed by Borrelia-positive 16S ribosomal RNA polymerase chain reaction and sequencing from valvular tissue and reported from Europe. Here we describe a case of Lyme endocarditis that, to our knowledge, is the first reported case confirmed by molecular diagnostics in the United States. Methods: We present the case of a 68-year-old man with progressive dyspnea who had mitral valve perforation with severe mitral valve insufficiency seen on transesophageal echocardiogram. Results: Subsequently resected valve tissue had signs of acute inflammation without organisms seen. Although blood and valve tissue cultures were negative, 16S ribosomal RNA polymerase chain reaction and sequencing demonstrated Borrelia burgdorferi. Conclusion: Lyme endocarditis can be a challenging diagnosis to confirm, given the rarity of cases and the need for molecular tools of resected valve tissue. It should be included among diagnostic possibilities in patients with culture-negative endocarditis who have exposure to ticks in endemic and emerging areas of Lyme disease.