Atrio-ventricular block as the first presentation of disseminated Lyme disease

Abstract A 36year old male patient presented to emergency cardiology department because of fatigability. ECG revealed high grade II atrio-ventricular block and bradycardia of 31beats/min. An erythema increasing in size to up to 7–8cm in diameter appeared a month earlier and spontaneously resolved within 10days. ELISA testing for antibodies against Borrelia burgdorferi IgM was positive and IgG titer was 1:40. Intravenous ceftriaxone 2g qod, and 0.5g metronidazole tid lead to regression of grade II block to grade I block within 2days. Grade I block persisted for an additional 10days. This is a relatively rare case of early occurrence of Lyme carditis within one month of exposure as the first sign of Lyme disease dissemination.