[Cardiac involvement in Lyme disease].

Cardiac manifestations of Lyme Borreliosis are relatively infrequent, occurring within weeks after the infectious tick bite (median of 21 days), and resulting at this stage from a direct borrelial infection of the myocardium, as indicated by reports of spirochete isolation from pericardium and myocardium. They may persist or appear in the late, tertiary phase of the illness, being then more likely due to infection-triggered autoimmunity. Lyme carditis typically presents with a fluctuating degree of atrioventricular block that spontaneously resolves in several days. Rarely, myocarditis may occur with or without pericardial involvement, in patients presenting with chest pain, ST depression or T wave inversion, mimicking an acute myocardial infarction, and various arrhythmias are reported, as well as pericardial effusion or heart failure. A complete recovery is usually observed, spontaneous or after antibiotherapy. Severe myocarditis or Pericarditis leading to death is exceptional. The diagnosis of Lyme carditis is based on the same association of clinical and laboratory features as in Lyme disease without cardiac involvement. But the occurrence of conduction disturbances in healthy young people suggests screening for other criteria of Lyme disease. The management of Lyme carditis does not differ from the treatment of Lyme disease without carditis and is mainly based upon the use of doxycycline or ceftriaxone.