The 12-lead electrocardiogram of “healthy” ambulatory subjects with positive lyme immunoserology

First described as a distinct clinical entity by Steere et al 1 in 1977, Lyme disease is now known to result from human infection with the spirochete Borrelia burgdorferi, an organism predominantly transmitted by Ixodes ticks. 2 Serologic testing for the presence of antibodies to B. burgdorferi, although imperfect, remains the single best, widely available, laboratory method to demonstrate exposure to the offending organism. 3 The most frequently reported cardiac manifestation of early (stage II) Lyme disease consists of variable degrees of atrioventricular block, including complete heart block. These conduction abnormalities have been documented by 12-lead electrocardiography and invasive electrophysiologic testing. 4,5 Despite advances in characterizing the acute expressions of this spirochetal infection in patients with definite disease, little has been learned regarding the significance of previous subclinical infection, specifically a “positive” Lyme test in an untreated asymptomatic person in an endemic area, with no history of clinically apparent Lyme disease. The aim of this study was to identify any electrocardiographic abnormalities that may be attributable to exposure to the Lyme spirochete in “healthy” seropositive subjects in a Lyme disease endemic area.