Phase 4 block of the right bundle branch suggesting His-Purkinje system involvement in Lyme carditis

Abstract

Lyme disease due to Borrelia burgdorferi infection causes a wide variety of signs and symptoms, including cardiac involvement termed Lyme carditis (LC).1–3 Though uncommon, LC is a well-established cause of atrioventricular (AV) block, typically at the AV node level, with infrequent involvement of the infranodal conduction system.1