Ethics & the CEO. Panel discussion.

When does a golden parachute become a bribe? How should an imperiled hospital serve both its mission and the interests of good business? H&HN put five executives on the spot with these questions, asking them to respond to a fictitious scenario inspired by today's headlines. Here's what they said.

Requests for medical advice from patients and families to health care providers who publish on the World Wide Web.

BACKGROUND: The Internet is a novel, rapidly growing means of worldwide public communication. METHODS: We reviewed all unsolicited electronic mail and other communications from nonmedical individuals requesting medical information over a 12-month period from the physician at 1 established site on the World Wide Web. This site was the only Internet site with a primary focus on cardiac arrhythmias. RESULTS: Seventy unsolicited inquiries were received from 39 patients and 20 family members (the sources of 11 inquiries are unknown) from 20 states, Washington, DC, and 9 foreign countries (locations of 15 inquiries are unknown). Follow-up was obtained in 22 cases. The inquiries concerned cardiological conditions in 67 cases (96%) and cardiac electrophysiologic conditions and procedures in 52 cases (74%). The goals of the inquiries were diagnosis (15), therapy (48), prognosis (1), and patient education (6). On follow-up of 22 cases, the people initiating the inquiries stated that they were reassured (16), consulted a general cardiologist (1), consulted a cardiac electrophysiologist (4), or visited a tertiary care electrophysiology center (1). CONCLUSIONS: The increasing use of the Internet by the general public seeking specific medical information for themselves and for their families suggests a widespread, unmet need for objective medical advice. This study demonstrates that the public can choose accurately whom to ask for subspecialty advice in the area of cardiovascular diseases. Professional societies and regulatory agencies should develop physician guidelines for providing medical advice over the Internet.

Validation of the EINTHOVEN model-based computerized electrocardiogram rhythm analysis system with three classes of clinical arrhythmias.

Rhythm analysis by commercial systems does not meet clinical needs well, because (1) differential diagnosis of complex rhythms is not performed, (2) common rhythms are often misdiagnosed, and (3) transitions between rhythms are not described. We have developed a model-based diagnostic software system named EINTHOVEN that is designed to address the above limitations. A demonstration is available on the World Wide Web at http:@einthoven.uokhsc.edu. The system has been validated using simple rhythms from introductory electrocardiogram (ECG) textbooks. We present here the results of evaluation with more complex rhythm strips taken from clinical records and intermediate-level ECG textbooks. Rhythm strips were described by the onset and offset of each electrical event (P wave, QRS complex, and T wave) and by a morphology classification for each event. The rhythms included a variety of supraventricular and ventricular rhythms. The analysis was considered correct if it named all correct diagnoses in a rhythm strip, incorrect if it completed the analysis and failed to name the correct diagnoses, and indeterminate if it failed to complete the analysis. The system was designed not to complete an analysis if it could not explain an entire rhythm by at least 1 pathophysiological model. The test rhythms were not used to develop the system. Forty-six of 56 test rhythms were diagnosed correctly, and 8 were not analyzed completely. The 2 incorrect diagnoses were atrial tachycardia with variable conduction (diagnosed as intermittent complete heart block) and atrial fibrillation (diagnosed as irregular junctional tachycardia). All 56 rhythms were diagnosed correctly after minor technical improvements to the system. The processing time of the system was 7.6-fold (range 1.5-to 16.9-fold) faster than the elapsed time of the individual records. These preliminary results suggest (1) that computer-based interpretation of complex rhythms is possible, (2) that further software development is necessary to reach a clinical level of accuracy, and (3) that there are no theoretical obstacles to achieving this goal.

EINTHOVEN and tolerance for human error: design issues in a decision support system for cardiac arrhythmia interpretation.

Decision support systems are becoming increasingly accepted in medical practice in the United States. Clinicians recognize the need for aid in interpretation of complex cardiac rhythms. The EINTHOVEN system is being developed to meet that need. In this paper, we address the need to deal with errors in the input due to inaccuracies in hand annotations by the inexperienced user and to interact with the user to correct them. Four specific types of input errors are described: missing waves, mispositioned waves, mislabeled waves, and extra waves. General and specific mechanisms by which these errors can be recognized and remedied are described. These results may be interesting as an example of the practical problems that arise in the design of real-world expert systems.

Automated analysis of intracardiac electrograms obtained during extrastimulus tests using a three-dimensional electrophysiology model.

Catheter ablation procedures are performed by highly trained and experienced cardiology subspecialists. Yet the massive amount of data produced during these procedures creates a data overload problem that can impede the performance of even the best practitioners. This may be evidenced by (1) overlooking important signal features, (2) misinterpreting the signals, and (3) misinterpreting catheter locations in the heart, all of which can lead to increased procedure duration, applications of radiofrequency energy to the wrong part of the heart, or both. This article presents the first results from a project aimed at developing a model-based system for interpreting intracardiac electrograms in near real time. The system is intended to assist physicians in interpreting the enormous amounts of data recorded during catheter ablation studies. It is an extension of the Einthoven system that has been extended to account for the three-dimensional relationships in the cardiac conduction system as recorded in the various intracardiac electrograms. The new three-dimensional cardiac conduction model and the enhancements to Einthoven's reasoning algorithms are presented. The locus of this study is on interpreting the results of ventricular extrastimulus tests. Data collected for this study and the output generated by the system are presented.

An algorithm for complete enumeration of the mechanisms of supraventricular tachycardias that use multiple atrioventricular, AV nodal, and/or Mahaim pathways.

The EINTHOVEN system is a model-based expert system that interprets the cardiac rhythm from the electrocardiogram. It simulates the expected behavior of realistic semi-quantitative cardiac models constructed by heuristic rules to generate interpretations that include both text descriptions and event-by-event causal explanations in the form of ladder diagrams. The simulation has been limited by an inability to predict all possible behaviors of hearts with more than one reentrant circuit. We now describe an algorithm that overcomes this limitation. Its output has been validated by an independent possibility-tree analysis. Timing and storage measurements are presented for models with up to three slow atrioventricular nodal pathways, four atrioventricular pathways, and a single atriofascicular (Mahaim) pathway. This is the first report in the literature of an algorithm that enumerates all possible mechanisms for reentrant supraventricular tachycardias that use atrioventricular, atrioventricular nodal, and/or atriofascicular pathways in humans.

A client/server system for remote diagnosis of cardiac arrhythmias.

Health care practitioners are often faced with the task of interpreting complex heart rhythms from electrocardiograms (ECGs) produced by 12-lead ECG machines, ambulatory (Holter) monitoring systems, and intensive-care unit monitors. Usually, the practitioner caring for the patient does not have specialized training in cardiology or in ECG interpretation; and commercial programs that interpret 12-lead ECGs have been well-documented in the medical literature to perform poorly at analyzing cardiac rhythm. We believe that a system capable of providing comprehensive ECG interpretation as well as access to online consultations will be beneficial to the health care system. We hypothesized that we could develop a client-server based telemedicine system capable of providing access to (1) an on-line knowledge-based system for remote diagnosis of cardiac arrhythmias and (2) an on-line cardiologist for real-time interactive consultation using readily available resources on the Internet. Furthermore, we hypothesized that Macintosh and Microsoft Windows-based personal computers running an X server could function as the delivery platform for the developed system. Although we were successful in developing such a system that will run efficiently on a UNIX-based work-station, current personal computer X server software are not capable of running the system efficiently.

Model-based interpretation of the ECG: a methodology for temporal and spatial reasoning.

A new software architecture for automatic interpretation of the electrocardiographic rhythm is presented. Using the hypothesize-and-test paradigm, a semiquantitative physiological model and production rule-based knowledge are combined to reason about time- and space-varying characteristics of complex heart rhythms. A prototype system implementing the methodology accepts a semiquantitative description of the onset and morphology of the P waves and QRS complexes that are observed in the body-surface electrocardiogram. A beat-by-beat explanation of the origin and consequences of each wave is produced. The output is in the standard cardiology laddergram format. The current prototype generates the full differential diagnosis of narrow-complex tachycardia and correctly diagnoses complex rhythms, such as atrioventricular (AV) nodal reentrant tachycardia with either hidden or visible P waves and varying degrees of AV block.

Model-based rhythm analysis of the ECG. Evaluation of a prototype implementation.

Current computer algorithms that interpret cardiac rhythms based solely on the surface electrocardiogram are limited, yet offer many benefits to health care. To address the limitations, novel computer algorithms for the automatic diagnosis of complex cardiac rhythms based solely on the surface electrocardiogram are presented. Using the hypothesize-and-test paradigm, a physiologic model of the cardiac conduction system and production rule-based knowledge are combined to reason about the time- and space-varying characteristics of complex heart rhythms. In addition, an evaluation of a prototype implementation of the algorithms is presented. A database of the time of onset, width, and shape classifications of each P wave, QRS complex, and T wave from 59 electrocardiographic strips was developed from an introductory textbook by hand-annotation using calipers. The database was not used in the development of the prototype. The prototype's diagnoses were reviewed by a clinical cardiac electrophysiologist who was not involved in the development process. Pair-wise comparisons among the prototype, textbook, and cardiac electrophysiologist, assuming either the textbook or electrophysiologist as the gold standard, were performed. The specific comparisons performed were prototype versus textbook, electrophysiologist versus textbook, prototype versus electrophysiologist, and textbook versus electrophysiologist. For all diagnostic categories, sensitivities of 88.0%, 97.2%, 78.6%, and 82.1%, respectively, and specificities of 99.2%, 98.5%, 99.7%, and 99.8%, respectively, were attained. When accounting for design and implementation limitations of the prototype, sensitivities of 93.0%, 98.5%, 89.1%, and 92.7%, respectively, and specificities of 99.4%, 99.2%, 99.6%, and 99.8%, respectively, were attained. The results indicate that these algorithms offer clinical advantages over currently available arrhythmia analysis systems.

Model-based interpretation of the ECG: a methodology for temporal and spatial reasoning.

A new software architecture for automatic interpretation of the electrocardiogram is presented. Using the hypothesize-and-test paradigm, a semi-quantitative physiological model and production rule-based knowledge are combined to reason about time- and space-varying characteristics of complex heart rhythms. A prototype system implementing the methodology accepts a semi-quantitative description of the onset and morphology of the P waves and QRS complexes that are observed in the body-surface electrocardiogram. A beat-by-beat explanation of the origin and consequences of each wave is produced. The output is in the standard cardiology ladder diagram format. The current prototype can perform the full differential diagnosis of 2:1 atrioventricular (AV) block, and can handle correctly complex rhythms such as AV nodal reentrant tachycardia with either hidden or visible P waves, and varying degrees of AV block.

Weaning patients from mechanical ventilation. A knowledge-based system approach.

The WEANing PROtocol (WEANPRO) knowledge-based system assists respiratory therapists and nurses in weaning post-operative cardiovascular patients from mechanical ventilation in the intensive care unit. The knowledge contained in WEANPRO is represented by rules and is implemented in M.1 by Teknowledge, Inc. WEANPRO will run on any IBM-compatible microcomputer. WEANPRO's performance in weaning patients in the intensive care unit was evaluated three ways: (1) a statistical comparison between the mean number of arterial blood gases required to wean patients to a T-piece with and without the use of WEANPRO, (2) a critique of the suggestions offered by the system by clinicians not involved in the system development, and (3) an inspection of the users acceptance of WEANPRO in the intensive care unit. The results of the evaluations revealed that using WEANPRO significantly decreases the number of arterial blood gas analyses needed to wean patients from total dependance on mechanical ventilation to independent breathing using a T-piece. In doing so, WEANPRO's suggestions are accurate and its use is accepted by the clinicians. Currently, WEANPRO is being used in the intensive care unit at the East Unit of Baptist Memorial Hospital in Memphis, Tennessee.

Physicians, financial managers join forces to control costs.

A case-mix management system relies on the skills of physicians, nurses, and financial managers to devise cost effective treatment plans and product line initiatives. By merging financial and clinical data, one hospital used the approach to identify practice patterns that were inflating expenses. Its case-mix management program--which consists of presenting economic studies of certain cases, profiling physician practice patterns, and budgeting by product lines--is designed to conserve resources while ensuring quality care.