Since 1987, publications in widely circulated medical journals have reported improved survival and lower hospital readmission rates when patients with heart failure and systolic dysfunction are treated with angiotensin-converting enzyme (ACE) inhibitors. We describe changes in ACE inhibitor use among patients hospitalized with heart failure between 1986 and 1993. Simultaneous trends in readmissions and survival rates are reported. Subjects were 612 consecutive patients hospitalized with a principal diagnosis of heart failure at an academic medical center during the period of Sept. 1, 1986, to Dec. 31, 1987 (interval I) or during the period Aug. 1, 1992, to Nov. 30, 1993 (interval II). Medical records were reviewed for 434 patients, consisting of all patients hospitalized with heart failure during interval II and a randomly selected 50% subset of patients hospitalized during interval I. Among 145 patients with systolic dysfunction whose medical records were reviewed, ACE inhibitor prescriptions significantly increased between interval I and interval II (43% vs 71%, p < 0.01, odds ratio 3.22, 95% confidence interval 1.62 to 6.42). Prescriptions of ACE inhibitors combined with digoxin and a diuretic also increased (37% vs 56%, p = 0.02, odds ratio 2.22, 95% confidence interval 1.14 to 4.32). Among all 612 patients, 6-month heart failure readmission rates increased from 13% to 21% (p = 0.02, odds ratio 1.79, 95% confidence interval 1.10 to 2.82). There was no significant change in survival rate between interval I and interval II, however, survival rate was marginally significantly improved among patients with systolic dysfunction. Our results suggest that drug-prescribing practices have significantly changed between 1986 and 1993. The absence of observed improvement in outcomes may result from changes in hospital admission criteria for heart failure.