of patients and providers, would be reasonable and prudent, and would represent the conclusions of published studies and the collective wisdom of many experts on IE and relevant national and international societies. Potential Consequences of Substantive Changes in Recommendations Substantive changes in recommendations could (1) violate long-standing expectations and practice patterns; (2) make fewer patients eligible for IE prophylaxis; (3) reduce mal- practice claims related to IE prophylaxis; and (4) stimulate prospective studies on IE prophylaxis. The Committee and others16 recognize that substantive changes in IE prophylaxis guidelines may violate long-standing expectations and prac- tice patterns by patients and healthcare providers. The Com- mittee recognizes that these new recommendations may cause concern among patients who have previously received anti- biotic prophylaxis to prevent IE before dental or other procedures and are now advised that such prophylaxis is unnecessary. Table 2 includes the main talking points that may be helpful for clinicians in reeducating their patients about these changes. To recommend such changes demands due diligence and critical analysis. For 50 years, since the publication of the first AHA guidelines on the prevention of IE,6 patients and healthcare providers assumed that antibiotics administered in association with a bacteremia-producing procedure effectively prevented IE in patients with underly- ing cardiac risk factors. Patients were educated about bacteremia-producing procedures and risk factors for IE, and they expected to receive antibiotic prophylaxis; healthcare providers, especially dentists, were expected to administer them. Patients with underlying cardiac conditions that carry a lifetime risk of acquisition of IE, such as mitral valve prolapse (MVP), had a sense of reassurance and comfort that antibiotics administered in association with a dental proce- dure were effective and usually safe to prevent IE. 