RATIONALE: Despite rapid advances in sophisticated cardiac imaging tools, auscultation using a simple stethoscope remains a powerful and fundamental skill used by both the generalist and specialist to discriminate disease from health, yet acquiring the knowledge and experience required for effective auscultation of the heart is still one of the most challenging and elusive hurdles faced by the health professional in training. Recent studies have shown that proficiency in cardiac auscultation is declining and have pointed out the need for improvements in the teaching and assessment of this clinical skill during generalists’ training (1-3). |
The Cardiac Auscultatory Recording Database (CARD) project is designed to improve the skill of cardiac auscultation among trainees at any level through use of an interactive, Internet-based virtual cardiology clinic designed specifically to offer rapid access to large numbers of complete cardiac examinations of actual patients in a searchable teaching format that gives immediate feedback to the user regarding skill level and specific deficiencies. Some of the theoretical advantages of using a digital recording database for teaching cardiac auscultation include the ability of the student to listen to various examples of the same finding in rapid succession in order to appreciate the natural variation that occurs between patients and build experience quickly, to slow down the heart rate and replay the example until timing of events is correctly understood, to simultaneously follow visually and compare graphic depictions of the abnormal sound alongside normal examples, and to filter frequencies and amplify the intensity of difficult to hear heart sounds so as to compensate for individual auditory limitations.
By providing this teaching module to health profession educators and trainees over the Internet, it is envisioned that study of this clinical skill, which has traditionally been possible only during limited hours, on certain clinical rotations, in an often suboptimal learning environment, can proceed at any time, in any location, at the students’ convenience and pace. By structuring the teaching module in an interactive, web-based format, we will be able to routinely update and modify the information and clinical examples, monitor the use and efficacy of the module, and follow and analyze the specific difficulties a given student has in learning auscultation. This data will be used to further tailor the module to address the specific needs of the individual student. While some audiotapes and a few CD-ROMs of heart sounds and murmurs are currently available, no comprehensive, interactive teaching module exists which focuses specifically on pediatric auscultation. Furthermore, to our knowledge, no comprehensive database of digitized cardiac examinations is currently available over the Internet. In addition to our interest in improving the skill of cardiac auscultation, we are using these recordings to develop computerized algorithms for automated diagnosis of heart disease. This work is being done with a team of engineers at the Johns Hopkins Applied Physics Laboratory.
PROGRESS TO DATE: In July 1997, we began recording and storing digitized heart sounds and clinical data on patients having an echocardiogram done in the Pediatric Cardiology Echocardiography Laboratory at the Johns Hopkins Outpatient Center. To date we have collected over 5000 individual recordings from over 1000 cardiology clinic visits by more than 900 different patients. The primary data files have been post processed into over 100,000 related sound files of 20 seconds duration each, in three different formats. An additional ~14,000 related image files depicting phonocardiograms, spectrograms, and 12-lead electrocardiograms from this patient population has also been collected in the database. Patients range in age from 1 day old to 80 years. Approximately 25% of the patients have no detectable heart disease by echocardiogram, with roughly 25% of these "normals" having at least one "innocent" heart murmur. Among the other patients with an abnormal echocardiogram, a wide range of diagnoses is represented, including these common congenital lesions: tetralogy of Fallot, atrial septal defects, common atrio-ventricular canal, mitral regurgitation, ventricular septal defects, coarctation of the aorta, bicuspid aortic valve, aortic stenosis, aortic regurgitation, mitral stenosis, mitral valve prolapse, pulmonary stenosis, idiopathic hypertrophic subaortic stenosis, patent ductus arteriosus.
The Cardiac Auscultatory Recording Database (CARD) has been developed using an industry standard relational database backbone. It is accessed via the Internet using a convenient, simple to use program designed specifically for this application. CARD contains patient demographic information, relevant historical and general physical examination data, electrocardiographic images and (ECG) diagnoses, echocardiographic diagnoses, auscultatory findings made by the clinician using the traditional stethoscope, all linked to a set of digitized recordings for each patient. The set of recordings includes at least one 20-second recording from each of 5 standard auscultatory areas, with additional recordings from other areas or using certain maneuvers when clinically indicated. All sound files are available in multiple formats and are easily downloadable or streamable for access with virtually any type of Internet connection. An auscultation trial in which sample files from the database were presented as unknown cases to members of the pediatric cardiology faculty at Hopkins to test the cardiologists ability to make accurate clinical judgements using these processed sounds, has recently been completed. Preliminary data analysis shows a high level of accuracy for diagnoses based on the recordings, similar to that from actual clinical auscultation. Further testing of the module among a group of trainees is planned. In addition, we have recently developed an automated screening method for detecting pathologic systolic murmurs (4).
Gaskin, PRA, Owens, SE, Talner, NS, Sanders, SP, Li, JS (2000) Clinical auscultation skills in pediatric residents. Pediatrics 105:1184-1187