In patients with underlying cardiac conditions associated with the highest risk of adverse outcome from IE (Table 3), IE prophylaxis for dental proce- Table 3. Cardiac Conditions Associated With the Highest Risk of Adverse Outcome From Endocarditis for Which Prophylaxis With Dental Procedures Is Reasonable Prosthetic cardiac valve or prosthetic material used for cardiac valve repair Previous IE Congenital heart disease (CHD)* Unrepaired cyanotic CHD, including palliative shunts and conduits Completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first 6 months after the procedure Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibit endothelialization) Cardiac transplantation recipients who develop cardiac valvulopathy *Except for the conditions listed above, antibiotic prophylaxis is no longer recommended for any other form of CHD. Prophylaxis is reasonable because endothelialization of prosthetic material occurs within 6 months after the procedure. Wilson et al Prevention of Infective Endocarditis 1745 dures is reasonable, even though we acknowledge that its effectiveness is unknown (Class IIa, LOE B). Compared with previous AHA guidelines, under these revised guidelines, many fewer patients would be candidates to receive IE prophylaxis. We believe that these revised guidelines are in the best interest of patients and healthcare providers and are based on the best available published data and expert opinion. Additionally, the change in emphasis to restrict prophylaxis for only those patients with the highest risk of adverse outcome should reduce the uncertainties among patients and providers about who should receive prophylaxis. 