The representativeness heuristic of the clinical features of infective endocarditis (IE) as described by Osler has undergone a significant change in developed countries.1,2 Previously, IE was a disease that commonly affected patients with predisposing valvular abnormalities caused by rheumatic carditis, with viridans group streptococci the most common causative pathogens.3 This presentation is currently seen in developing countries, where rheumatic heart disease is still prevalent. In developed countries, mitral valve prolapse (MVP) is now thought to be the most common predisposing cardiac condition in patients with IE.2 Several recent studies from passively reported case series suggest that Staphylococcus aureus is now the most frequently identified causative pathogen.1 These more recent clinical observations of IE characteristics, however, are based on data that come primarily from large, tertiary care centers4,5 and may not reflect true changes in the epidemiology of IE but rather temporal changes in referral patterns. Thus, population-based investigations are needed to more accurately characterize IE in the United States.