Complete AV block in Lyme carditis: an important differential diagnosis

Area of Science:

• Cardiology
• Infectious Diseases
• Tick-borne Illnesses

Background:

• Lyme disease, a tick-borne illness caused by Borrelia burgdorferi, can lead to cardiac complications.
• Cardiac involvement, known as Lyme carditis, often presents with conduction abnormalities.

Observation:

• A 37-year-old male presented with dizziness and fatigue, exhibiting significant bradycardia (35/min) and third-degree atrioventricular (AV) block on ECG.
• Initial examinations showed no other abnormalities, but subsequent serological tests confirmed Lyme disease.

Findings:

• The patient's third-degree AV block resolved rapidly following intravenous antibiotic treatment with ceftriaxone.
• This rapid resolution strongly suggests Lyme carditis as the direct cause of the severe conduction disturbance.

Implications:

• Highlights the importance of considering Lyme disease in the differential diagnosis of unexplained heart block, even with non-specific initial symptoms.
• Emphasizes the effectiveness of timely antibiotic therapy in reversing cardiac manifestations of Lyme disease.
• Underscores the potential for Lyme carditis to cause significant and potentially reversible conduction abnormalities.