The sensitivity of TTE is about 60%, whereas TEE is ~90%
A negative TTE does not rule out the diagnosis of IE
To assess for anatomy and complications when TTE is positive (especially if large vegetation, valvular insufficiency, or suspected paravalvular extension)
When the pre-test probability of IE is high or anatomy is unique: Prosthetic valve, congenital heart disease, previous IE, S. aureus bacteremia
Complications of IE suspected: heart failure, paravalvular abscess, new AV block
Poor quality TTE: obstructive lung disease, obesity