Table 1 Integrating clinical and laboratory data for rational use of echocardiography in patients with suspected native valve infective endocarditis

Clinical criteria for diagnosis of infective endocarditis (adapting Duke Criteria)

Major criteria

1. Positive blood cultures for infective endocaritis:

a. Typical microorganisms for infective endocarditis, including viridans strep, S. bovis, HACEK or community acquired Staph aureus or enterococcus OR

b. Microorganisms from persistent positive blood cultures, at least two positive cultures drawn >12 hours apart

2. Evidence of endocardial involvement:

a. New valvular regurgitation on clinical exam (worsening or changing of pre-existing murmur not sufficient)

Minor criteria

1. Predisposition: predisposing heart condition or intravenous drug use

2. Fever: temperature >38 C on two separate occasions

3. Vascular phenomenon: major arterial emboli, septic pulmonary infarcts, mycotic aneurysms, intracranial hemorrhage, conjunctival hemorrhages, Janeway lesions

4. Immunological phenomenon: glomerulonephritis, Osler's nodes, Roth's spots and rheumatoid arthritis

5. Microbiological evidence: positive blood cultures but does not a meet a major criteria as defined above

6. Serological evidence of active infection with organism consistent with endocarditis

High Likelihood: two major or one major and three minor clinical criteria

-Transthoracic and transesophageal echocardiography to assess prognosis or complications

Intermediate likelihood: one major or three minor clinical criteria

-TTE as initial test. If the echo is positive, then treat appropriately.

-TEE if the patient has high risk echocardiographic features on TTE or if clinical suspicion remains after negative or nondiagnostic TTE

Low likelihood: firm alternative diagnosis

-No echocardiography for diagnosis. Look for and treat alternative diagnosis