Alterations in myocardial function during bacterial infective cardiomyopathy.

Area of Science:

• Cardiology
• Infectious Diseases
• Pathology

Background:

• Bacterial endocarditis can lead to systemic complications.
• Myocardial involvement in endocarditis is not fully understood.
• Assessing cardiac function during infection is crucial.

Purpose of the Study:

• To evaluate myocardial function in rabbits with experimental Streptococcus viridans endocarditis.
• To compare cardiac status in infected, uninfected catheterized, and sham-operated rabbits.
• To investigate the development of infective cardiomyopathy.

Main Methods:

• Cardiac catheterization in rabbits.
• Induction of Streptococcus viridans infection.
• Assessment of myocardial function at 3 and 6 days post-infection.
• Biochemical analysis of serum markers.
• Electrocardiographic monitoring.
• Hemodynamic measurements (left ventricular pressure).

Main Results:

• Infected rabbits showed left heart hypertrophy, edema, mononuclear cell infiltration, muscle degeneration, lung congestion, and pleural fluid accumulation.
• Elevated serum enzymes (creatine phosphokinase, lactic dehydrogenase, glutamic oxaloacetic transaminase) and ECG abnormalities were observed in both infected and uninfected groups.
• Infected rabbits exhibited decreased serum calcium, magnesium, and sodium, with increased potassium.
• Myocardial contractility and relaxation were significantly depressed in infected animals, with decreased maximal contractile element velocity.
• Isolated perfused hearts from infected animals demonstrated reduced contractile force and altered relaxation dynamics.

Conclusions:

• Experimental bacterial endocarditis induces significant myocardial dysfunction in rabbits.
• Infective cardiomyopathy is associated with impaired cardiac contractility and relaxation.
• These findings provide evidence linking bacterial endocarditis to heart failure.