Myocardial work indices and cardiac magnetic resonance in the diagnosis and follow-up of Lyme carditis presenting with intermittent complete heart block

This case report explores the spectrum and mechanisms of myocardial involvement in Lyme carditis, integrating clinical and imaging findings to better understand the disease course and its management implications. While conduction abnormalities are the most well-recognized cardiac manifestation of Lyme carditis, our findings highlight the importance of myocardial work assessment by echocardiography in the early stage of the disease and by cardiac magnetic resonance in the late stage. These insights may guide clinicians in early recognition, targeted therapy, and prevention of adverse cardiac outcomes in Lyme carditis and other forms of myocarditis. We report the case of a 44-year-old male presenting with complete atrioventricular block. Myocardial work assessment by echocardiography was performed to investigate the underlying etiology, revealing findings suggestive of an inflammatory myopericardial syndrome as the cause of the conduction abnormality. The Suspicious Index in Lyme Carditis suspicious (SILC) score indicated an intermediate probability of Lyme infection, which was subsequently confirmed by laboratory testing. The patient was treated with intravenous ceftriaxone, resulting in resolution of the conduction disturbance and obviating the need for pacemaker implantation. During follow-up, myocardial work parameters were reassessed, and cardiac magnetic resonance imaging was performed, both supporting remission with residual changes and providing additional prognostic insights.