Objective: To identify asymptomatic heart involvement early in the course of Lyme borreliosis by analysis of electrocardiograms (ECGs) of patients with solitary erythema migrans (EM). Methods: We enrolled in this prospective study 220 consecutive previously healthy patients, receiving no medication, who were diagnosed with typical solitary EM at our Lyme borreliosis Outpatient Clinic in 1998. Their ECG findings were compared with the ECG results in 165 age and sex-matched healthy persons. Results: Three patients with EM but none in the control group had first degree AV block (p = 0.319). Second and third degree AV blocks, electrocardiographic signs of pericarditis, myocarditis or rhythm disturbances were not found in any of the ECGs. Comparison of findings in patients with EM and the control group revealed statistically significant differences in frequency (66.2 1.47beats/min in patients with EM versus 68.4 +/- 1.52 beats/min in controls; p = 0.043), duration of Q (0.013 +/- 0.001 s in patients with EM versus 0.015 +/- 0.001 s in controls; p < 0.001), and in depth of S (0.135 +/- 0.016mV in patients with EM versus 0.104 +/- 0.012 mV in controls; p < 0.05), but not for several other ECG parameters. These differences were found in females as well as in males. Comparison of ECG findings in subgroups of patients with EM (grouped according to EM characteristics such as length of incubation, duration of skin lesion and the presence of associated systemic symptoms) did not reveal any significant difference. Conclusions: AV blocks, the most typical heart manifestation of early disseminated Lyme borreliosis, are a rare finding in patients with solitary EM, and in our study their frequency did not differ from that in the control group. We do not have a reliable explanation for the shorter duration of Q and deeper S wave in patients with EM compared with age and sex-matched controls.
