An approach to use of echocardiography for diagnosis of native valve infective endocarditis

IE: infective endocarditis; TTE: transthoracic echocardiogram; TEE: transesophageal echocardiogram.
* The diagnosis of IE should be suspected in patients with fever (with or without bacteremia) and/or relevant cardiac risk factors (prior IE, presence of a prosthetic valve or cardiac device, history of valvular or congenital heart disease) or noncardiac risk factors (intravenous drug use, indwelling intravenous lines, immunosuppression, or a recent dental or surgical procedure).
¶ Low risk/low suspicion for IE: for example, patient with fever and previously known cardiac murmur and no other stigmata of IE.
Δ High risk/high suspicion for IE: for example, S. aureus bacteremia, new murmur, prior IE, congenital heart disease. Patients with prosthetic heart valve or intracardiac device are also high risk; the approach to diagnosis of IE in these circumstances is discussed further separately (refer to the UpToDate topics on prosthetic valve endocarditis and cardiac device infections).
◊ High-risk clinical features include new atrioventricular block (prolonged PR interval), persistent fever despite appropriate antimicrobial therapy, and Staphylococcus aureus bacteremia; high-risk echocardiographic features include large or mobile vegetations, valvular insufficiency, suggestion of paravalvular extension, or ventricular dysfunction.
§ Patients with high suspicion for paravalvular complications (such as prolonged PR interval) and indeterminate or negative TEE may warrant additional imaging such as cardiac computed tomography; refer to text for further discussion.