Lyme Carditis in a Transplanted Heart: A Rare Cause of Early Conduction Abnormalities.

BACKGROUND

Lyme disease, caused by Borrelia burgdorferi, is the most common vector-borne infection in North America. Cardiac involvement occurs in approximately 1% to 10% of untreated infections and most commonly manifests as atrioventricular conduction abnormalities.

CASE SUMMARY: A 29-year-old man with arrhythmogenic right ventricular cardiomyopathy underwent orthotopic heart transplantation. Early postoperatively he developed atrial flutter progressing to complete heart block despite preserved graft function and absence of rejection. Donor history revealed recent tick exposure. Warthin-Starry staining of surveillance endomyocardial biopsy demonstrated rare spirochetes consistent with Borrelia species. The patient received intravenous ceftriaxone for presumed donor-derived Lyme carditis but ultimately required permanent pacemaker implantation.

DISCUSSION: This case highlights Lyme carditis as a rare potential cause of early conduction abnormalities after heart transplantation.