Should a patient with second-degree atrioventricular block (AVB) and Lyme disease be referred to an electrophysiologist (EP)?

Management of Second-Degree Atrioventricular Block in Lyme Disease

Patients with second-degree atrioventricular block (AVB) due to Lyme disease should be referred to an electrophysiologist (EP) for evaluation and management, especially if they have symptomatic bradycardia or evidence of hemodynamic compromise. 1

Assessment and Initial Management

Cardiac Evaluation

• Perform ECG in all patients with suspected Lyme carditis 1
• Look for specific signs and symptoms of cardiac involvement:
  • Dyspnea, edema, palpitations, lightheadedness, chest pain, syncope
  • Exercise intolerance, presyncope, pericarditic pain
  • Evidence of pericardial effusion or elevated cardiac biomarkers 1

Risk Stratification

• High-risk features requiring hospitalization:
  • PR interval >300 milliseconds
  • Other significant arrhythmias
  • Clinical manifestations of myopericarditis
  • Hemodynamic compromise 1

Management Algorithm

1. For Hemodynamically Stable Patients

• Initiate appropriate antibiotic therapy:
  • Outpatients with mild symptoms: Oral antibiotics (doxycycline, amoxicillin, cefuroxime axetil, or azithromycin) for 14-21 days 1
  • Monitor ECG regularly to assess for progression of conduction abnormalities

2. For Hemodynamically Unstable Patients

• Hospital admission with continuous ECG monitoring 1
• IV ceftriaxone initially until clinical improvement, then transition to oral antibiotics to complete 14-21 days of total therapy 1
• For symptomatic bradycardia refractory to medical therapy:
  • Temporary pacing modalities rather than permanent pacemaker 1, 2, 3
  • Options include transcutaneous pacing until transvenous temporary pacing can be established 1

Role of the Electrophysiologist

The EP specialist plays a crucial role in:

1. Determining the level and severity of the AV block
2. Managing temporary pacing needs
3. Monitoring for resolution of conduction abnormalities
4. Making decisions about long-term management if conduction abnormalities persist

Follow-up Recommendations

• Close cardiac monitoring during antibiotic treatment
• Repeat ECG after completion of antibiotic therapy
• Long-term follow-up to ensure complete resolution of conduction abnormalities 2, 3

Important Considerations

• Avoid permanent pacemaker implantation: Lyme carditis-associated AV block is typically reversible with appropriate antibiotic therapy 1, 3, 4
• Prognosis: The long-term outlook is excellent with appropriate treatment, with most cases of heart block resolving within 1-3 weeks 3, 4
• Timing of resolution: Complete heart block rarely persists more than 1 week after initiating appropriate antibiotics 4

Common Pitfalls to Avoid

1. Failure to recognize Lyme disease as a cause of AV block, especially in young patients from endemic areas
2. Premature implantation of permanent pacemakers before adequate antibiotic treatment
3. Inadequate monitoring during the acute phase of illness
4. Insufficient follow-up after apparent resolution of conduction abnormalities

In conclusion, EP referral is essential for patients with second-degree AVB due to Lyme disease to ensure appropriate management of conduction abnormalities, proper implementation of temporary pacing if needed, and to avoid unnecessary permanent pacemaker implantation.