Excerpt:

Lyme disease is a tick-borne spirochetal infection that may
affect the heart.
Cardiac manifestations include conduction disturbances and other
pathologies of the heart. We report on a 37-year old male, who
was admitted to the emergency department because of Cardiac manifestations Physical examination and the initial
laboratory values revealed no abnormalities. The patient’s
electrocardiogram on admission revealed newly diagnosed
bradycardia due to atrioventricular heart block. The ventricular
heart rate was 35/min. The patient was admitted to the ICU. Lyme
serology and Western blot were positive for Borrelia antibodies.
After institution of antibiotic therapy with ceftriaxone,
atrioventricular heart block resolved rapidly. We therefore have
to assume that in this patient Lyme carditis was the cause of
third-degree AV block.