Lyme carditis manifesting with sinoatrial exit block: a case report

Area of Science:

• Cardiology
• Infectious Diseases
• Electrophysiology

Background:

• Lyme disease, caused by *Borrelia burgdorferi*, is a common North American and European vector-borne illness.
• Cardiac involvement, known as Lyme carditis (LC), often affects the heart's conductive tissue, typically causing atrioventricular block.
• This study explores the less common involvement of the sinus node in Lyme carditis.

Observation:

• A 31-year-old female presented with syncope due to severe sinoatrial (SA) block, a manifestation of Lyme carditis.
• The patient experienced prolonged asystole (over 12 seconds) indicative of SA exit block.
• Diagnostic evaluation confirmed Lyme carditis as the cause of the cardiac dysfunction.

Findings:

• The case demonstrates that Lyme carditis can lead to high-degree SA block, impacting the heart's primary pacemaker.
• Antibiotic therapy with a third-generation cephalosporin completely resolved the SA block and associated syncope.
• No permanent pacemaker was required, and the patient remained free of sinus pauses during a 12-month follow-up.

Implications:

• Sinus node dysfunction should be considered in the differential diagnosis of patients with suspected Lyme carditis.
• Effective antibiotic treatment can potentially prevent the need for permanent pacemaker implantation in these cases.
• This highlights the importance of early diagnosis and management of Lyme disease to prevent severe cardiac complications.