Sensitivity of Echocardiographic Types

Transthoracic echocardiography (TTE)

TTE has a sensitivity of about 65% but is unable to pick up vegetation smaller than 2 mm and is hampered by technical issues like body habitus and emphysema.

It is a very specific test detecting vegetation in >90% of patients with endocarditis [6].

Due to low sensitivity, TTE should not be used for screening unless there is low pre-test probability of Endocarditis.

TTE is inadequate for evaluation of prosthetic valves, localised abscess formation and vegetation less than 2 mm in size.

Trans-oesophageal echocardiography (TOE)

Trans-oesophageal echocardiography has a sensitivity of 90% and is much better at detecting cardiac structural abnormalities [6]. It is therefore the investigation of choice in patients with a high pre-test probability of endocarditis as well as in patients with known structural heart disease, prosthetic valves or an unsuitable body habitus.

A negative scan does not completely rule out infective endocarditis, especially early in the disease and, where index of suspicion is high, this is an indication for a repeat examination.

Learning Bite

TOE has a higher sensitivity than TTE and is the investigation of choice.