The HDP (Heart Disease Program) is a large diagnostic program, developed to assist physicians with the diagnosis of heart disease, particularly those conditions leading to hemodynamic dysfunction and heart failure.

There are now over 200 codes for diagnoses and physiological states covering all main areas of cardiology and related areas of general medical diagnoses (respiratory, renal and gastrointestinal systems are included if they may complicate cardiac problems or have a similar presentation) After user registration and assurance, that the program will only be used for research purpose, the user is presented with a large form covering the history, symptoms, physical examination and laboratory results—essentially the same data that the physician uses to determine a diagnosis. Once this information is entered and submitted, forms are presented asking for details on important findings. The HDP then runs on a different server. The results are presented to the user: 1. The input with comments about any assumption made because of missing input. 2. Leading hypothesis outlined including the presumed causality, supporting findings for the physiologic states, and pertinent negatives. The intent is to provide enough detail about the hypothesis to allow the user to intelligently accept or reject it and know what findings are the basis for that decision. 3. Matrix of the hypotheses in the differential indicating what significant physiologic states each includes. This helps the user to distinguish those parts of the hypothesis for which there are altemate viable explanations from those with relatively solid support. Included are lines explaining the alternate physiologic states in the same way as the first hypothesis. 4. The different explanations for each finding found in the differential.

Evaluation: The HDP has been evaluated during the last few years with cases by residents who were treating the patients. In this evaluation of 114 patients, the HDP had a significantly higher sensitivity for both the gold standard (60%) and the cardiologist´s diagnoses (58%), than the physicians did (39%, 34%). The main challenge is that it took an average of slightly less than 15 minutes for the residents to enter their cases- excellent by the standards of other diagnostic programs, but too long for routine use by physicians. (If online data were available, this could be reduced to 5 minutes).

The HDP is accessible via the Internet at URL: http://medg.lcs.mit.edu/projects/hdp
or, http://medg.lcs.mit.edu/projects/hf.html

Clinical Decision Making Group, MIT Lab for Computer Science, Cambridge andTufts, New England Medical Center, Boston

Clinical Decision Making Group, MIT LAB for Computer Science http://www.medg.lcs.mit.edu