Complications of infective endocarditis may be considered as those that involve the heart and adjacent structures or those that are extracardiac. Congestive heart failure is the most common serious complication of infective endocarditis and is the leading cause of death among patients with this infection. In patients with severe heart failure unresponsive to medical therapy after 24 to 48 hours, prompt cardiac valve replacement should be considered, irrespective of the duration of preoperative antimicrobial therapy. We believe that all patients with bacterial infective endocarditis who are stable hemodynamically and who have not had multiple large emboli should receive at least one course of antimicrobial therapy in an attempt to sterilize the infected valve before cardiac valve replacement is considered. Most patients with multiple major embolic events should undergo cardiac valve replacement or debridement of the infected valve. The technical limitations and the experience with two-dimensional echocardiography in patients with infective endocarditis who have valve vegetations demonstrated by echocardiography are not yet sufficient to justify cardiac valve replacement solely on the basis of echocardiographic findings. The highest frequency of major embolic events occurs in association with infections that produce large mobile valve vegetations, such as those caused by Haemophilus parainfluenzae and other slow-growing fastidious gram-negative bacilli, fungi (especially Aspergillus), and nutritionally variant viridans streptococci.