A Case of Lyme Carditis Presenting with Atrial Fibrillation

Lyme carditis presenting as atrial fibrillation in a healthy young male

We present a case of a 23-year-old man coming with palpitations, found to be in atrial fibrillation (AF). He was initially managed with metoprolol for rate-controlled therapy-reverted to normal sinus rhythm and discharged home. He returned a few days later-this time in varying degrees of atrioventricular block including transient complete heart block. He was empirically started on intravenous ceftriaxone for suspected Lyme carditis, which subsequently led to the resolution of high-degree heart block. Lyme immunoglobulin G (IgG) and IgM returned positive. Follow-up ECG after the course of antibiotic exhibited normal sinus rhythm. AF is a rare presentation of Lyme disease but still exists. It should be considered in terms of appropriate treatment, especially in Lyme-endemic areas.

Lyme carditis presenting as atrial fibrillation

The incidence of Lyme disease in the USA is 8 per 100 000 cases and 95% of those occur in the Northeastern region. Cardiac involvement occurs in only 1% of untreated patients. We describe the case of a 46-year-old man who presented with chest pressure, dyspnoea, palpitations and syncope. He presented initially with atrial fibrillation with rapid ventricular response, a rare manifestation of Lyme carditis. In another hospital presentation, he had varying degrees of atrioventricular block including Mobitz I second-degree heart block. After appropriate antibiotic treatment, he made a full recovery and his ECG normalised. The authors aim to urge physicians treating patients in endemic areas to consider Lyme carditis in the workup for patients with atrial fibrillation and unexplained heart block, as the associated atrioventricular nodal complications may be fatal.