Each of these comorbid conditions independently increases the risk of adverse outcome from IE, and they often occur in combina- tion, which further increases morbidity and mortality rates. Additionally, there may be long-term consequences of IE. Over time, the cardiac valve damaged by IE may undergo progressive functional deterioration that may result in the need for cardiac valve replacement. In native valve viridans group streptococcal or enterococcal IE, the spectrum of disease may range from a relatively benign infection to severe valvular dysfunction, dehiscence, congestive heart failure, multiple embolic events, and death; however, the underlying conditions shown in Table 3 virtually always have an increased risk of adverse outcome. For example, patients with viridans group streptococcal prosthetic valve endocarditis have a mortality rate of 20% or greater,106 109 whereas the mortality from patients with viridans group streptococcal native valve IE is 5% or less.108,110 116 Similarly, the mortality of enterococcal prosthetic valve endocarditis is higher than that of native valve enterococcal IE.107,108,114,117 Moreover, patients with prosthetic valve endocarditis are more likely than those with native valve endocarditis to develop heart failure, the need for cardiac valve replacement surgery, perivalvular extension of infection, and other complications. Patients with relapsing or recurrent IE are at greater risk of congestive heart failure and increased need for cardiac valve replacement surgery, and they have a higher mortality rate than patients with a first episode of native valve IE.118 124 Additionally, patients with multiple episodes of native or prosthetic valve IE are at greater risk of additional episodes of endocarditis, each of which is associated with the risk of more Published series regarding endocarditis in patients with CHD are underpowered to determine the extent to which a specific form of CHD is an independent risk factor for morbidity and mortality. 