Some patients present with vague symptoms that include malaise, fatigue, anorexia, or decreased functional capacity. Less commonly, the diagnosis of CIED infection is suspected in patients with fever of undefined origin who harbor no local inflammatory changes at the generator-pocket site. At least 2 sets of blood cultures should be obtained before the initiation of antimicrobial therapy in all patients with suspected CIED infection; some patients with bloodstream infection may not manifest systemic toxicity or peripheral leukocytosis. Posi- tive blood cultures, particularly due to staphylococcal spe- cies, provide a strong clue that the clinical syndrome is due to CIED infection. Patients should be educated about the need to be evaluated for CIED infection by cardiologists or special- ists in infectious diseases if they develop fever or blood- stream infection for which there is no initial explanation. Transesophageal echocardiography (TEE) may be useful in demonstrating CIED-related endocarditis in adults. Because of its poor sensitivity, transthoracic echocardiography is frequently not helpful in ruling out a diagnosis of lead-related endocarditis, particularly in adults. Moreover, patients can develop both right-sided (lead-related) and left-sided endo- carditis; the sensitivity of TEE for left-sided involvement and for perivalvular extension of infection is superior to that of transthoracic echocardiography. Additionally, visualization of the lead in the proximal superior vena cava from TEE views may identify tissue along that region that is difficult to visualize by other methods. TEE examination is critical among patients with S aureus bacteremia, because the rate of endocarditis is significant.67 Several prognostic features may be better defined on transthoracic echocardiography than on TEE, such as pericardial effusion, ventricular dysfunction and dyssynchrony, and pulmonary vascular pressure estimations. 