Sidney Abraham

Computer Extraction of Electrocardiographic Parameters

T HIS STUDY was undertaken to demonstrate the feasibility of use of a computer program to extract automatically, without human intervention, clinically useful measurements of the parameters of an electrophysiologic tracing. The electrocardiogram was selected as the most suitable model of an electrophysiologic signal from which to extract data because of the large backlog of electrocardiographic data on subjects known to be norrnal or abnormal. Moreover, widespread use of electrocardiograms facilitates future statistical validation of the results of computer derived data.

Effects of age and heart disease on the QRS axis during the seventh through the tenth decades

Abstract The mean frontal plane QRS axis of 658 patients between 60 and 94 years of age was obtained: 313 (48 per cent) were males, and 345 (52 per cent) were females. There were 308 patients without cardiovascular disease (Group I) and 350 patients with cardiovascular disease (Group II). These were divided by age into 5-year subgroups. In Group I the mean of the QRS axis showed no significant trend to the left with age, whereas in Group II there was a marked leftward trend in the ninth and the tenth decades. In the last three 5-year subgroups the means of the frontal plane QRS axis in Group I were 16.8, 23.2, and 22.2 degrees, respectively, and corresponding values in Group II were 5.1, 0.6, and −15.6 degrees. The differences between the means in the last two subgroups are statistically significant. The proportion with left axis deviation (−30 degrees or above) was greater in Group II than in Group I, particularly in the last two 5-year subgroups. The percentages were as follows: Group II, 26 and 42; Group I, 12 and 8.

Description of a computer program for analysis of the forced expiratory spirogram I. Instrumentation and programming

Abstract Manual measurement of the forced expiratory spirogram (FES) is time consuming, tedious, and subject to observer variation. Application of computer capabilities to the acquisition, analysis and interpretation of the FES has led to the development of a program that is precise and accurate. The instrumentation and programming are presented as Part I of a two-part article, the second section of which is devoted to an assessment of the methods of validation applied to the program.

METROLOGY IN CARDIAC DISEASE DETECTION.

A statement attributed to Lord Kelvin defines science as the stage of knowledge at which the subject matter can be defined in numbers. Conversely, when the subject is undefinable in numbers it is not science, but is art. The goal of art is uniqueness, and the goal of science is routine reflection. The artistic method produces the unique achievement; science produces repeatable results. Since the importance of numbers lies in their use in those fields in which we want routine, repeatable results, it is a happy event in medicine when science decreases the realm of art. To hasten that day we must devote attention to metrology in disease. We use the word metrology and not simply measurement because metrology encompasses the science of precise interrelationship of measurements and their weights in each unique situation. In medicine, metrology can be utilized most fruitfully to study combinations of significant values that can help us detect early disease processes to help us differentiate between diseases that present similar signs and symptoms

APPLICATION OF STATISTICAL TECHNIQUES IN ANALYSIS OF ELECTROCARDIOGRAPHY

Sidney Abraham Instrumenration Field Sration, Heart Disease Control Program Division of Chronic Diseases. U. S. Department of Health, Education and Welfare, Washington, D. C. Juan B. Calatayud and Patrick A. Gorman Department of Medicine,? The George Washington University Hospital Washington, D. C. Cesar A. Caceres Insrrumentarion Field Sration, Hearr Disease Control Program Division of Chronic Diseases, U. S. Department of Health, Education and Welfare, Washingron, D. C.

Tape-recorded heart sounds: A comparison with mediate auscultation

An attempt has been made to evaluate the relative efficiency of utilizing tape-recorded heart sounds for the detection (screening) of children who may have significant cardiac disease and who thus would require more extensive and precise studies to identify their cardiac status. The results from such a method are compared with those obtained by mediate auscultation.