The surgeon (or one of his assistants) enters, in a computer file, information on open-heart surgical procedures through a remote terminal located in the recovery room. Clinical and historical findings, complications occurring during the immediate postoperative period, and postmortem data when applicable are entered in the course of the hospital stay or after discharge. Relevant information entering the computer system in other hospital departments is automatically incorporated in the open-heart surgery file. A final multicopy operative report is printed in the recovery room shortly after the surgical procedure is completed. All information on patients in the file constitutes a permanent and dynamic data base that is accessible at any time from any remote terminal in the hospital computer system. This data base contains an average of 500 items of information per surgical procedure and is available via an on-line retrieval program for both quality control purposes and extrapolation of prognostic data on new patients.