From the Guidelines
ECG abnormalities in bacterial endocarditis are primarily conduction abnormalities, such as first-degree AV block, bundle branch blocks, or complete heart block, which suggest extension of infection into the conduction system, and management requires prompt initiation of appropriate antibiotics and potential surgical intervention. The most common ECG findings include:
- Conduction abnormalities, such as first-degree AV block, bundle branch blocks, or complete heart block
- New arrhythmias, particularly atrial fibrillation
- Signs of myocardial ischemia if septic emboli affect coronary circulation Management of bacterial endocarditis requires:
- Prompt initiation of appropriate antibiotics based on blood culture results, typically for 4-6 weeks
- Empiric therapy often includes a combination of vancomycin (15-20 mg/kg IV every 8-12 hours) plus ceftriaxone (2g IV daily) until culture results guide targeted therapy, as recommended by the American Heart Association 1
- For native valve endocarditis caused by viridans streptococci, penicillin G (12-18 million units IV daily) or ceftriaxone (2g IV daily) is recommended
- Staphylococcal endocarditis often requires nafcillin or oxacillin (2g IV every 4 hours) plus gentamicin in selected cases Surgical intervention is necessary for:
- Heart failure due to valve dysfunction
- Uncontrolled infection
- Prevention of embolic events Regular echocardiography is essential to monitor vegetation size, valve function, and potential complications like abscess formation or valve perforation, as emphasized by the European Society of Cardiology guidelines 1. ECG monitoring throughout treatment helps detect developing conduction abnormalities that might require temporary pacing or other interventions. According to the most recent guidelines, patients with complicated IE should be referred early and managed in a reference centre with immediate surgical facilities 1.
From the Research
ECG Abnormalities in Bacterial Endocarditis
- ECG conduction changes are common in endocarditis, occurring in 26% of patients 2
- These changes are associated with increased mortality and invasive infection 2
- Patients with ECG conduction changes are more likely to be male and have prosthetic valves 2
- The presence of ECG conduction changes is a significant predictor of mortality, with 31% of patients with these changes dying during hospitalization compared to 15% without changes 2
Management Strategies for Bacterial Endocarditis
- The choice of antibiotic therapy is determined by the identity and antibiotic susceptibility of the infecting organism, the type of cardiac valve involved, and patient characteristics such as drug allergies 3
- Treatment with aqueous penicillin or ceftriaxone is effective for most infections caused by streptococci 3
- A combination of penicillin or ampicillin with gentamicin is appropriate for endocarditis caused by enterococci that are not highly resistant to penicillin 3
- Vancomycin should be substituted for penicillin when high-level resistance is present 3
- Native valve infection by methicillin-susceptible staphylococci is treated with nafcillin, oxacillin, or cefazolin, with the addition of gentamicin for the first three to five days to accelerate clearing of bacteremia 3
Antibiotic Treatment Regimens
- Penicillin-aminoglycoside regimens are accepted therapy for enterococcal endocarditis 4
- Combination antibiotic therapy may be used for other forms of bacterial endocarditis, but its use is controversial 4
- The American Heart Association recommends specific antibiotic regimens for different types of endocarditis, including those caused by streptococci, staphylococci, and enterococci 3, 5, 6