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. Healthcare providers, especially dentists, felt a sense of obligation and professional and legal responsibility to protect their patients from IE that might result from a procedure. On the basis of recommendations in this revised document, substantially fewer patients will be recommended for IE prophylaxis. Cases of IE either temporally or remotely associated with an invasive procedure, especially a dental procedure, have frequently been the basis for malpractice claims against healthcare providers. Unlike many other infections for which there is conclusive evidence for the efficacy of preventive therapy, the prevention of IE is not a precise science. Because previously published AHA guidelines for the prevention of IE contained ambiguities and inconsistencies and were often based on minimal published data or expert opinion, they were subject to conflicting interpretations among patients, health- care providers, and the legal system about patient eligibility for prophylaxis and whether there was strict adherence by healthcare providers to AHA recommendations for prophy- laxis. This document is intended to identify which, if any, patients may possibly benefit from IE prophylaxis and to define, to the extent possible, which dental procedures should have prophylaxis in this select group of patients. Accord- ingly, the Committee hopes that this document will result in greater clarity for patients, healthcare providers, and consult- ing professionals. The Committee believes that recommendations for IE prophylaxis must be evidence based. A placebo-controlled, multicenter, randomized, double-blinded study to evaluate the efficacy of IE prophylaxis in patients who undergo a dental, GI, or GU tract procedure has not been done. 