Lyme carditis manifesting with sinoatrial exit block: a case report

Lyme disease is the most common vector-borne disease in North America and Europe. Infection with the spirochete Borrelia burgdorferi complex can involve cardiac tissue causing Lyme carditis (LC). Due to the infection of conductive tissue, LC typically presents with varying degrees of atrioventricular conduction block. Here, we provide the first evidence that conductive tissue of the sinus node can be involved in LC resulting in higher degree sinoatrial (SA) block with concomitant syncope.

We report the case of an otherwise healthy 31-year-old female presenting with LC manifesting with SA exit block causing asystole over 12 s with concomitant syncope. Signs of SA block completely resolved with antibiotic treatment with a third-generation cephalosporin. The patient did not require permanent pacemaker implantation and had no sinus pauses after 12 months of follow-up as confirmed via implantable loop recorder.

The possibility of LC in patients with sinus node dysfunction should be considered, as adequate antibiotic therapy can spare patients from potentially unnecessary pacemaker implantation.