Lyme carditis: a reversible cause of complete atrioventricular block

A 54-year-old American woman presented with an episode of syncope. This had occurred against a background of several days of dizziness and palpitations. Her medical history included Bell’s palsy, which had been diagnosed three weeks earlier. On examination, she had a resting bradycardia of 31 beats per minute and her electrocardiogram demonstrated third-degree atrioventricular (AV) block. She was referred to cardiology for consideration of permanent pacemaker implantation. Given her facial nerve palsy and AV block, a diagnosis of Lyme borreliosis was suspected. Within 48 hours of initiation of ceftriaxone, she reverted to sinus rhythm, albeit with a marked first-degree AV block. Subsequent serology confirmed the diagnosis. Reversible causes of complete AV block should always be considered and appropriate therapy may avoid the need for permanent pacemaker insertion.

Keywords Atrioventricular block, Lyme borreliosis, Lyme carditis

Declaration of Interests  No conflict of interests declared.