Bacterial endocarditis is an infection of the endocardium (the inner lining of the heart, including the heart valves) caused by bacteria. It is the most common form of infective endocarditis (IE), which is the broader term used in modern medical practice to encompass infections caused by bacteria, fungi, and other organisms.
The condition occurs when bacteria enter the bloodstream and colonise the endocardial surface, particularly where there is pre-existing structural abnormality such as a damaged or prosthetic heart valve, a ventricular septal defect, or other congenital cardiac abnormality. Bacteria most commonly implicated include Staphylococcus aureus (the leading cause of acute endocarditis), Streptococcus viridans (associated with subacute endocarditis, often following dental procedures), and Enterococcus species.
Infected deposits called vegetations form on the valve leaflets or endocardial surface. These can damage valve function, obstruct blood flow, and release emboli (fragments that travel to the brain, kidneys, spleen, and other organs). Treatment involves prolonged intravenous antibiotics (typically 4 to 6 weeks) and, in many cases, surgical valve repair or replacement. Bacterial endocarditis can cause cardiac arrest through valve destruction, emboli to the coronary arteries, or arrhythmias.
For a comprehensive description of infective endocarditis including its symptoms, investigations, treatment, and relevance to cardiac arrest, see Endocarditis.
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