OBJECTIVE: To compare the prognostic value of qualitative estimates of left ventricular function with that of routine simple quantitative indices used in echocardiography. DESIGN: Retrospective follow up study. SETTING: University hospital. PATIENTS: The records of 2,964 patients who had undergone echocardiography and who could be traced on the family health services register were examined; 919 cases were included in the study, and a further 458 were used to validate the statistical models for prognostic assessment. There were 928 exclusions on the basis of referral for or diagnosis of alternative conditions, and 659 because of incomplete collection of the qualitative and quantitative data used in the study. MAIN OUTCOME MEASURE: Survival over the study period. RESULTS: A qualitative "eyeball" estimate of left ventricular function was of prognostic significance (relative risk of poor v good, 2.248; P << 0.001; 95% confidence interval 1.620 to 3.119). None of the quantitative echocardiographic indices was of independent prognostic significance when all variables were tested simultaneously in the regression model. CONCLUSIONS: A qualitative echocardiographic estimate of left ventricular dysfunction is of prognostic value, supporting the view of many cardiologists who use their overall impression of left ventricular function at echocardiography as the basis for treatment decisions.