The clinical outcome and long-term follow-up of 130 consecutive patients (141 episodes) with active infective endocarditis who were treated between 1966 and 1991 were analyzed. There was a shift toward a higher proportion of referred patients (39 to 78%), patients aged > 60 years (11 to 41%) and urgent surgical treatment (11 to 44%). Medical treatment was administered in 98 patients (70%); 30-day mortality was 27%. Surgery was performed in 43 patients (30%), with an operative mortality of 26%; 9 of 14 patients (64%) who underwent operation within the first week of admission died. Patients with severe heart failure are at the highest risk for early mortality (relative risk = 21.1; 95% confidence interval 7.4-60.3). Referred patients were much more often treated surgically than were nonreferred patients (48 versus 14%) and had a lower operative mortality (24 vs 30%). Nonreferred patients were more often treated medically (86 vs 52%) and with lower mortality (19 vs 39%). The total follow-up time was 730 patient-years; only 1 patient was considered lost to follow-up. The overall cumulative 5-year and 10-year survival after hospital discharge for patients after urgent surgery were 84 +/- 7% and 53 +/- 7%, respectively, and for those after medical treatment 84 +/- 5% and 77 +/- 6%, respectively. The probability of remaining free of late events (recurrent endocarditis, late valve replacement or death) during 5 and 10 years for patients after urgent surgery was 84 +/- 7% and 53 +/- 15%, respectively, and for those after medical treatment 59 +/- 6% and 40 +/- 7%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)