Background: This study aimed to determine the epidemiologic, clinical, microbiologic characteristics, and inhospital outcome of infective endocarditis(IE) in Argentina and compare the results with those of the 1992 IE national survey. Methods: A prospective, multicenter study was conducted in 82 hospitals representing 16 of 24 provinces of Argentina. Patients with diagnosis of IE according to the Duke criteria were surveyed during an 18- month period. Results: From 470 surveyed episodes of IE, 390 cases were classified as definite and 80 as possible IE. The mean age of the definite IE cases was 58.5± 17.3 years; male sex, 70.0% ; and male- female ratio, 2.3 ∶ 1. Pathological evidence of IE was available in 26.2% . There was no previously known heart disease in 35.1% , and the proportion of prosthetic valve IE was 15.9% . Causative microorganisms were streptococci, 38.3% (Streptococcus viridans 27.0% , Streptococcus bovis 5.2% , others 6.1% ); enterococci, 10.2% ; staphylococci, 36.7% (Staphylococcus aureus 29.8% , coagulase- negative sta- phylococci 6.9% );HACEK group, 6.1% ; fungal, 1.4% ; and polymicrobial, 2.0% . Blood culture results were negative in 10.8% . Surgical treatment was performed in 26.2% , and the overall inhospital mortality was 24.6% . Patients from the 2002 survey were older(58.5± 17.3 vs 51.3± 18.7 years, P< .01) and more frequently had underlying heart disease(64.9% vs 55.0% , P< .01): degenerative valve disease(11.5% vs 4.8% , P< .01), congenital heart disease(9.5% vs 4.2% , P< .01), and prosthetic valve IE(15.9% vs 8.5% , P< .01). Conversely, the prevalence of rheumatic valve disease was significantly less than in the 1992 survey(5.4% vs 13.0% , P< .01). Conclusions: The EIRA- 2 survey shows that the clinical profile of IE has changed in Argentina. Currently, patients with IE are older and have a higher frequency of underlying heart disease, degenerative valve disease, and prosthetic valve IE than previously. The incidence of staphylococcal IE has increased. Inhospital mortality remains high, suggesting that more aggressive measures are needed for the early identification, prevention, and treatment of IE. Background: This study aimed to determine the epidemiologic, clinical, microbiologic characteristics, and inhospital outcome of infective endocarditis (IE) in Argentina and compare the results with those of the 1992 IE national survey. Methods: A prospective, multicenter study was conducted in 82 Plants representing 16 of 24 provinces of Argentina. Patients with diagnosis of IE according to the Duke criteria were surveyed during an 18- month period. Results: From 470 surveyed episodes of IE, 390 cases were classified as definite and 80 as possible IE. The Mean age of the confirmed IE cases was 58.5 ± 17.3 years; male sex, 70.0%; and male-female ratio, 2.3: 1. Pathological evidence of IE was available in 26.2%. There was no previously known heart disease in 35.1% and the proportion of prosthetic valve IE was 15.9%. Causative microorganisms were streptococci, 38.3% (Streptococcus viridans 27.0%, Streptococcus bovis 5.2%, others 6.1%); enterococci, 10.2%; staphylococci, 36.7 % (Staphylococcus aureus 29.8%, coagulase- negative sta- phylococci 6.9%); HACEK group, 6.1%; fungal, 1.4%; and polymicrobial, 2.0%. Blood culture results were negative in 10.8% , and the overall inhospital mortality was 24.6%. Patients from the 2002 survey were older (58.5 ± 17.3 vs 51.3 ± 18.7 years, P <.01) and more frequently had underlying heart disease (64.9% vs 55.0%, P <.01 ): degenerative valve disease (11.5% vs 4.8%, P <.01), congenital heart disease (9.5% vs 4.2%, P <.01), and prosthetic valve IE (15.9% vs 8.5%, P <.01) Conversely, the prevalence of rheumatic valve disease was significantly less than in the 1992 survey (5.4% vs 13.0%, P <.01). Conclusions: The EIRA-2 survey shows that the clinical profile of IE has changed in Argentina. , patients with IE are older and have a higher frequency of underlying heart disease, degenerative valve disease, and prosthetic valve IE than previously. The incidence of staphylococc al IEhas increased. Inhospital mortality remains high, suggesting that more aggressive measures are needed for the early identification, prevention, and treatment of IE.