In a separate study, the risk of IE per 100 000 patient-years was 271 in patients with congenital aortic stenosis and 145 in patients with ventricular septal defect.105 In that same study, the risk of IE before closure of a ventricular septal defect was more than twice that after closure. Although these data provide useful ranges of risk in large populations, it is difficult to utilize them to define accurately the lifetime risk of acquisition of IE in an individual patient with a specific underlying cardiac risk factor. This difficulty is based in part on the fact that each individual cardiac condition, such as RHD or MVP, represents a broad spectrum of pathology from minimal to severe, and the risk of IE would likely be influenced by the severity of valvular disease. CHD is another underlying condition with multiple differ- ent cardiac abnormalities that range from relatively minor to severe, complex cyanotic heart disease. During the past 25 years, there has been an increasing use of various intracardiac valvular prostheses and intravascular shunts, grafts, and other devices for repair of valvular heart disease and CHD. The diversity and nature of these prostheses and procedures likely present different levels of risk for acquisition of IE. These factors complicate an accurate assessment of the true lifetime risk of acquisition of IE in patients with a specific underlying cardiac condition. On the basis of the data from Steckelberg and Wilson91 and others,2 it is clear that the underlying conditions discussed above represent a lifetime increased risk of acquisition of IE compared with individuals with no known underlying cardiac condition. 