[Dyspnea and palpitations in a 39-year-old male patient].

A 39-year-old male patient presented with dyspnea and palpitations. The electrocardiogram (ECG) showed a first degree atrioventricular (AV) block and frequent atrial extra systoles. Within the following 48 h the AV block gradually developed into a third degree intermittent complete AV block. The patient history included an untreated tick bite 2 months before presentation. The serological proof of antibodies confirmed the diagnosis of Lyme carditis and antibiotic treatment with ceftriaxon i.v. was initiated. Normal AV conduction finally resumed and the symptoms subsided completely without any further clinical consequences.