Acute Legionnaires’ Disease–Associated Complete Heart Block

Legionnaires’ disease is a systemic disease caused by Legionella species that predominantly affects the lungs; however, extrapulmonary manifestations including cardiac involvement have been reported. We present a case of a 79-year-old woman who presented with cough, reduced appetite, and syncope and was found to be in third-degree atrioventricular block. The patient had a positive urine Legionella antigen with a finding on computed tomography of the chest of bilateral infiltrates. Despite antibiotic therapy, permanent pacemaker was implanted for persistent complete heart block. At 2-week follow-up, however, patient had regained intrinsic conduction. This case highlights Legionnaires’ disease as a potential reversible cause of complete heart block.