Role of transthoracic and transesophageal echocardiography in right-sided endocarditis: one echocardiographic modality does not fit all.

The added value of transesophageal echocardiography (TEE) over transthoracic echocardiography in the assessment of left-sided infective endocarditis has been extensively validated in the literature. Little research has dealt with the role of echocardiography in right-sided infective endocarditis (RSE), however. In this review, the differences between RSE and left-sided endocarditis and the different types of RSE according to the types of patients who have the disease are described. Both issues have important implications for echocardiographic workup. Moreover, a systematic echocardiographic protocol to avoid missing right-sided vegetations and several specific morphologic aspects of RSE are reviewed. Normal right-sided structures, which may mimic vegetations, particularly when the clinical picture is compatible, are described. Finally, the value of transthoracic echocardiography and TEE in RSE is reviewed according to the publications available. The diagnostic yield of transthoracic echocardiography is comparable with that of TEE in intravenous drug users. On the contrary, TEE is mandatory in patients with cardiac devices. A Bayesian-based diagnostic approach is proposed for a third poorly characterized group of patients with RSE who are not drug addicts, have no cardiac devices, and have no left-sided endocarditis (the "three no's" endocarditis group).