We report a case of
Lyme carditis in an otherwise-healthy young male who presented to the Emergency Department (ED) with syncope and a possible seizure. This patient, without documented history of
Lyme disease, acutely developed third-degree atrioventricular (AV) block with episodic asystole, which required placement of a transvenous pacemaker in the ED and resolved only after the patient had been placed on ceftriaxone. We discuss the significance of
Lyme carditis and its increasing prevalence, and review the current literature. We also recommend appropriate screening modalities for patients with known
Lyme disease, or an atypical profile for cardiac abnormalities.