Mitral Valve Endocarditis: A Rare Manifestation of Lyme Disease.

Valvular involvement in Lyme disease is rare. Confirmation of Borrelia species as the causative agent with polymerase chain reaction was done in a few cases in Europe and the United States. We describe a case of mitral regurgitation with a preoperative diagnosis of myxomatous mitral valve degeneration. During surgery, the surgeon suspected infective rather than degenerative etiology; the results of tissue cultures were negative. However, universal bacterial polymerase chain reaction on explanted valve tissue detected Borrelia burgdorferi DNA. If a surgeon suspects infective endocarditis at the time surgery, appropriate specimens should be sent for histopathologic analysis, culture, and polymerase chain reaction assay.