Although echocardiography has been incorporated into the diagnostic algorithm of patients with suspected infective endocarditis (IE), systematic usage in clinical practice remains ill defined. To determine the diagnostic accuracy of detecting vegetations using harmonic transthoracic echocardiography (hTTE) as compared to transesophageal echocardiography (TEE) in patients with an intermediate likelihood of native valve IE.
Between 2004 and 2005, 36 consecutive inpatients with an intermediate likelihood of disease were prospectively evaluated by hTTE and TEE.
Of 36 patients (21 males with a mean age of 57 ├é┬▒ 15 years, range 32 to 86 years), 19 patients had definite IE by TEE. The sensitivity for the detection of vegetations by hTTE was 84%, specificity of 88%, positive predictive value (PPV) of 89% and negative predictive value (NPV) of 82%. The association between hTTE and TTE interpretation for the presence and absence of vegetations were high (kappa = 0.90 and 0.85 respectively).
In patients with an intermediate likelihood of native valve IE, TTE with harmonic imaging provides diagnostic quality images in the majority of cases, has excellent concordance with TEE and should be recommended as the first line test.
Infective endocarditis (IE) is a diagnostic and therapeutic challenge that is associated with high patient morbidity and mortality.  The diagnosis and management of IE have changed dramatically over the past 40 years, in particular the complementary use of echocardiography. [2,3] In addition to positive blood cultures and a new regurgitant murmur, echocardiographic findings has become one of the major Duke criteria for IE providing objective evidence of endocardial involvment.  Despite the higher sensitivity and specifity of transesophageal echocardiography (TEE) in the detection of valvular vegetations and characterization of complications, [4-7] transthoracic echocardiography (TTE) remains the initial procedure of choice in patients with suspected IE, due to its noninvasive nature and low cost. 
Although echocardiography has been incorporated into the diagnostic approach for patients with suspected IE, systematic usage in clinical practice is still not optimally defined. In patients with a high clinical likelihood of IE, the practical role of TTE for diagnostic purposes is low. [9,10] In the same context, echocardiography is often requested for patients with a transient fever, a nonregurgitant murmur, or both, who have a very low likelihood for the disease, with a low diagnostic yield. [9,10] Strict adherence to indications for TTE and TEE may help to facilitate more appropriate use and accurate diagnosis in patients who are most likely to benefit from screening echocardiography, in those patients with intermediate likelihood of the disease. 
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