MINI-SYMPOSIUM Echocardiography in infective endocarditis

S ince Dillon and colleagues in 1973 described valvar vegetations by M mode echocardiography, the technique has assumed an increasingly important role in the assessment and management of endocarditis. The development of two dimensional and later transoesophageal echocardiography (TOE) has significantly improved the non-invasive detection of vegetations. Moreover, echoDoppler studies provide clinically important information on the presence and degree of valvar destruction and their haemodynamic consequences, as well as on the existence of perivalvar infection. The diagnostic strategy proposed by Durack and colleagues (the Duke criteria) combined echocardiographic findings with clinical and microbiological data. Three echocardiographic findings were considered to be major criteria for the diagnosis of endocarditis: (1) presence of vegetations defined as mobile echodense masses implanted in a valve or mural endocardium in the trajectory of a regurgitant jet or implanted in prosthetic material with no alternative anatomical explanation; (2) presence of abscesses; or (3) presence of a new dehiscence of a valvar prosthesis. Abnormal echocardiographic findings not fulfilling those definitions were considered minor criteria. More recently the use of TOE has resulted in better imaging and therefore doubtful findings are not considered minor criteria any longer. Since the definite diagnosis of endocarditis requires the presence of two major criteria, or one major and three minor criteria, it is clear that echocardiography has assumed a crucial role in the diagnosis of the disease, particularly when blood cultures are negative.