Infective endocarditis (IE) is an infection of the endocardium (the inner lining of the heart, including the heart valves) caused by microorganisms, most commonly bacteria. It is the term used in modern clinical practice to describe this condition, distinguishing it from rare non-infective inflammatory forms. Bacterial endocarditis is the most common form, though fungal endocarditis occurs in immunocompromised patients.
The infection typically occurs when microorganisms enter the bloodstream (bacteraemia) and colonise the endocardial surface, particularly where there is pre-existing structural abnormality such as a damaged or prosthetic valve. Infected deposits called vegetations form, which can damage the valve, obstruct blood flow, and release emboli to the brain, kidneys, and other organs. Infective endocarditis can cause cardiac arrest through valve destruction, coronary embolism, or arrhythmias.
Diagnosis requires blood cultures, echocardiography (to visualise vegetations and assess valve damage), and clinical assessment using the Duke criteria. Treatment involves prolonged intravenous antibiotics (typically 4 to 6 weeks) and, in many cases, surgical valve repair or replacement.
For a full description of infective endocarditis including risk factors, symptoms, investigations, treatment, and relevance to cardiac arrest, see the comprehensive Endocarditis entry.
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