Lyme-induced cardiac problems persist despite antibiotic treatment

The young woman was admitted to the emergency department with acute pleuritic chest pain and shortness of breath. (Pleuritic chest pain is characterized by sudden and intense sharp, stabbing, or burning pain in the chest when inhaling and exhaling.)

The woman exhibited only mild tachycardia (100/min). However, “Considering the suspicion of acute myocarditis, the patient was admitted to an intensive cardiac care unit,” the authors state.

During hospitalization, cardiac monitoring revealed several asymptomatic episodes of paroxysmal AV block, including second-degree Mobitz I AV block, second degree AV block, and high-grade AV block.

Although there was no evidence of tick exposure or skin lesions, clinicians ordered testing for Lyme disease, which was positive by Western blot. “… an IgM Western-Blot test was performed, confirming positivity and recent Borrelia spp. infection.”

The patient was diagnosed with Lyme disease with cardiac manifestations of high-grade AV block. She was treated with a 4-week course of IV ceftriaxone, which led to a complete resolution of chest pain and shortness of breath.

However, the AV conduction disturbance continued after 4 weeks of antibiotic treatment. And subsequently, the woman was given an alternative diagnosis of extrinsic idiopathic paroxysmal AV block (“adenosine-sensitive AV block”).

This could be an extremely rare course of Lyme carditis, or the patient may have had asymptomatic AV conduction problems that surfaced when she developed Lyme disease, according to the authors.

“The patient was started on theophylline 400 mg twice daily, and after one week of treatment, the Holter monitoring demonstrated a significant reduction in AV conduction disturbances,” the authors state.

At her 18-month follow-up appointment, the woman continued to have fewer AV conduction disturbances, no cardiac complaints, and no need for a permanent pacemaker.

Authors conclude:

“This case illustrates a challenging scenario of [Lyme carditis] with high grade AV block, which persisted after appropriate antibiotic treatment and had key features supporting the diagnosis of extrinsic idiopathic paroxysmal AV block (‘adenosine sensitive AV block’).”