Clinical parameters for the diagnosis of perivalvular extension of IE are inadequate. Persistent bacteremia or fever, recurrent emboli, heart block, heart failure, or a new patho- logical murmur in a patient with IE on appropriate antibiotics may suggest extension.303 Only aortic valve involvement and current IDU have been prospectively identified as independent risk factors for perivalvular abscess.297 On ECG, new atrio- ventricular block has a positive predictive value of 88% for abscess formation but low (45%) sensitivity.298 Patients at risk for perivalvular extension of IE require prompt evaluation. The size of vegetations is not helpful for predicting perivalvular extension.297 The sensitivity of TTE for detecting perivalvular abscess is low (18% to 63% in pro- spective and retrospective studies, respectively).305,306 TEE dramatically improves the sensitivity for defining periannular extension of IE (76% to 100%) while retaining excellent spec- ificity (95%) and positive and negative predictive values (87% When combined with spectral and color Doppler techniques, TEE can demonstrate the distinc- tive flow patterns of fistulas and pseudoaneurysms and can rule out communications from unruptured abscess cavities. Because of these combined capabilities, TEE is recommended for the initial assessment of any patient suspected of having perivalvular extension of IE. A small number of patients with periannular extension of infection or myocardial abscess may be treated successfully without surgical intervention.307,308 These patients potentially include those who have smaller (<1 cm) abscesses and who do not have complications such as heart block, echocardiographic evidence of progression of abscess during therapy, valvular dehiscence, or insufficiency. Such patients should be monitored closely with serial TEE; TEE should be repeated at intervals of 2, 4, and 8 weeks after completion of antimicrobial therapy. Surgery for patients with perivalvular extension of IE is directed toward eradication of the infection and correction of hemodynamic abnormalities. 