Lyme Carditis

Background

• Lyme carditis is the cardiac manifestation of Lyme disease which includes components of myocarditis, pericarditis, and pancarditis, as well as conduction abnormalities such as atrioventricular (AV) block.
• Reported incidence of cardiac involvement in Lyme disease is 0.3%-4%.
• Direct myocardial invasion by Borrelia burgdorferi spirochetes and the subsequent immunologic process leads to an exaggerated inflammatory response.
• Complications include AV-conduction disorders, myocarditis, pericarditis, and rarely, acute heart failure or cardiogenic shock.

Evaluation

• Suspect Lyme carditis in patients who have been to a Lyme disease-endemic area in the previous 6 months who have clinical manifestations consistent with Lyme carditis, including fever, rash, arthralgia, light-headedness, dizziness, syncope, and dyspnea, as well as advanced heart block.
• For patients presenting with high-degree atrioventricular block and suspicion of Lyme carditis, evaluate using Suspicious Index in Lyme Carditis (SILC) score.
• For low suspicion of Lyme carditis (SILC score 0-2 points), consider administering empiric standard treatment for high-degree atrioventricular block (pacing).
• For intermediate suspicion of Lyme carditis (SILC score 3-6 points) or high suspicion (SILC score 7-12 points), consider ordering serological tests and serum troponins.
• Obtain an electrocardiogram to assess presence and degree of atrioventricular block.
• For cases where Lyme carditis may mimic acute coronary syndrome with elevated cardiac biomarkers, consider echocardiography or cardiac magnetic resonance imaging.

Management

• Antibiotic treatment for Lyme carditis is based upon treatment setting:
  • For outpatients, consider oral antibiotics for 14-21 days over IV antibiotics (Weak recommendation).
  • For hospitalized patients, consider initial use of IV ceftriaxone over oral antibiotics, then switch to oral antibiotics to complete treatment (Weak recommendation).
• Regimens for hospitalized patients with serious presentation of Lyme carditis (defined as high-degree atrioventricular block or first-degree atrioventricular block with PR interval ≥ 300 milliseconds) may include:
  • ceftriaxone 2g IV once daily for 10-14 days (up to 28 days) in adults followed by one of
    • doxycycline 100 mg orally twice daily for total antibiotic course of 14-21 days
    • amoxicillin 500 mg orally 3 times daily for total antibiotic course of 14-21 days
    • cefuroxime axetil 500 mg orally twice daily for total antibiotic course of 14-21 days
• Regimens for mild presentation of Lyme carditis (defined as first-degree atrioventricular block with PR interval < 300 milliseconds) may include one of
  • doxycycline 100 mg orally twice daily for 14-21 days in adults
  • amoxicillin 500 mg orally 3 times daily for 14-21 days in adults
  • cefuroxime axetil 500 mg orally twice daily for 14-21 days in adults
• Pacing
  • Use temporary pacing for bradycardia that is either symptomatic or occurs with high-risk electrocardiographic features (such as alternating bundle branch block) (Strong recommendation).
  • Options for temporary pacing include temporary pacing with standard transvenous temporary pacemaker lead or modified temporary-permanent transvenous pacing.
• For Lyme carditis complicated by acute heart failure or cardiogenic shock, see Acute Heart Failure or Cardiogenic Shock.