Transesophageal echocardiography should be done when Patients have a prosthetic valve (where TTE sensitivity is limited) Transthoracic echocardiogram is nondiagnostic Diagnosis of infective endocarditis has been established clinically (done to detect perforations, abscesses, and fistulas) Serial TEE enables diagnosis of complications that evolve during treatment, such as increasing vegetation size or abscess formation.