[Cardiac manifestations of Lyme disease. Apropos of 2 cases].

Lyme disease, a well-known entity in the United States, has featured only rarely in the French literature. We report two cases from the Cardiology Department with acute symptomatic atrio-ventricular block. The illness begins with migratory chronic erythema, which is the best marker of the condition. This is followed by neurological, joint and cardiac manifestations. Cardiac involvement consists essentially in A-V block of varying severity, which rapidly regresses. Until the recent discovery of the arthropod vector responsible (Ixodes dammini), the diagnosis was clinical and was confirmed by negative serological results for the other infectious agents. Penicillin and tetracycline are effective at the skin lesion stage. It is important to recognise this condition since there is no case of complete A-V block lasting longer than 2 weeks.