[Transient complete AV block as a sequela of Borrelia myocarditis]

A 49-year-old man suddenly developed dyspnoea, sweating, fever (up to 38.5 degrees C), vertigo and angina. After emergency admittance to hospital the ECG showed 3 degrees A-V block, requiring temporary pacemaker insertion. The patient reported that a month before he had been bitten, probably by a tick. Serological tests demonstrated a recent Borrelia infection (rise of IgG antibody titre to 1:2048, IgM antibody titre to 1:128). Coronary angiography excluded any haemodynamically significant coronary heart disease as a cause of the conduction disorder. Myocardial biopsy showed changes pointing to a past myocarditis. This suggested Borrelia infection as the cause of the complete A-V block. Under treatment with broad-spectrum antibiotics for 15 days the fever subsided and the ECG became normal. Shortly before discharge, an elevated pulmonary wedge pressure on 150 W exercise indicated persistence of mild left-ventricular failure.