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Biomedical subjects

M E Tavel

Publications and source records attributed to M E Tavel.

At least 37 records · Page 2Linked to original sources

Enhanced auscultation with a new graphic display system.

BACKGROUND: To provide an objective method to support and teach auscultation, a new portable system (graphic display system) was evaluated for graphic display and printing of heart sounds. METHODS: Ninety-one patients from three institutions, with a variety of heart sound abnormalities, were studied by two examiners. A graphic recording was made in each and compared with the auscultatory findings. RESULTS: The findings of the graphic system confirmed the auscultatory impressions of both examiners in 77 (85%) of the 91 cases. Brief sound transients, such as split second sounds and ejection sounds, third heart sounds, and prosthetic opening and closing sounds, were all regularly recorded with the graphic system, often allowing resolution when examiners were in disagreement. Graphic recordings commonly were at variance with examiners in detecting fourth sounds, possibly because of examiners' difficulty in distinguishing these from split first sounds as well as limitations of the graphic system itself. High-pitched murmurs of low intensity (< grade 2), as exemplified by those of aortic and mitral regurgitation, were occasionally missed by the graphic system, probably because of baseline interference by background noise. CONCLUSIONS: The graphic display system can often provide more information than can be obtained by standard auscultation alone, especially in the detection of low-frequency and multiple sounds, and in the accurate timing of intervals. It is often unable to detect soft high-frequency murmurs. Permanent records allow for more objective comparison of the auscultatory findings of various examiners at different times. This system provides an excellent means by which auscultation skills may be taught or enhanced, especially since its speed and portability allow immediate feedback for comparison with auditory perceptions.

Computer Graphics↗

Audibility of the fourth heart sound. Relationship to presence of disease and examiner experience.

To determine the meaning of an audible fourth heart sound (S4), 51 subjects (21 normal and 30 abnormal persons), aged between 38 and 74 years (mean, 55.4 years), were examined by nine "blinded" physicians (four cardiologists, five house staff officers). Audibility scores were compared with phonocardiographic, echocardiographic, and hemodynamic measurements. An S4 was recorded graphically in 35 (68.6%) of all 51 subjects and splitting of the first sound (S1), in 37 subjects (72.5%). The abnormal group did not differ significantly from the normal subjects in incidence of recordable S4 or splitting of S1. Audibility of S4, however, correlated with its recorded amplitude, size, and palpability of the presystolic apical impulse, left ventricular systolic and diastolic diameters, and history of myocardial infarction. Despite variation among examiners, house staff officers were likelier than cardiologists to believe an S4 present even in cases lacking a recordable S4 and in normal subjects and were more apt to believe an S4 present when splitting of S1 was identified graphically. We conclude that an audible S4 continues to provide evidence for cardiac disease, and that increasing examiner experience renders this finding fairly specific. Less experienced examiners are likelier to confuse splitting of S1 with the S4, suggesting that training should be focused on means to improve this differentiation.

Adult↗

Strategy for the detection and management of coronary artery disease. "Physiology before anatomy".

A strategy for the diagnosis of ischemic heart disease should be based on knowledge of the prevalence of the disease in population subgroups. Asymptomatic patients should not be routinely screened. Asymptomatic patients or patients with nonanginal chest pain should have both a positive exercise electrocardiogram and stress nuclear scan before a diagnosis of ischemic heart disease is justified or arteriography is recommended. Patients with atypical angina should be evaluated with exercise radionuclide ventriculography. Coronary arteriography is rarely needed for diagnosis and is most properly used as a preoperative evaluation of a patient who has symptoms uncontrolled by medical management, or in whom a significant amount of myocardium is at risk as determined by physiologic testing with exercise electrocardiography or stress nuclear techniques.

Angina Pectoris↗

Spectral analysis of heart sounds: relationships between some physical characteristics and frequency spectra of first and second heart sounds in normals and hypertensives.

Frequency analysis of heart sounds has been gaining recognition as a possible indicator of several heart and valve diseases, although a comprehensive study of normal heart sounds has not been published. Relating the frequency content of normal heart sounds to certain physical characteristics surrounding the generation of these sounds could lead to a valuable diagnostic tool and give a better understanding of the mechanism of heart sounds production. In this study, the first and second heart sounds from seventy-four normal, and seven hypertensive volunteers were recorded, digitized and analysed using a Fast Fourier Transform algorithm. Statistical analysis was used to relate physical characteristics (sex, blood pressure, and body surface area) of the subjects to the frequency content of normal heart sounds and to compare normal and hypertensive heart sounds. Statistical analysis showed that the major concentration of energy, for both first heart sound (S1) and second heart sound (S2), is below 150 Hertz (Hz) which may indicate that both sounds are caused by vibrations within the same structure, possibly the entire heart. However S2 spectra have greater amplitude than S1 spectra above 150 Hz, which may be due to vibrations within the aorta and pulmonary artery. Relationships observed between body surface area, sex, blood pressure, and the frequency content of heart sounds indicate that as heart size increases, the amplitude of the frequency coefficients above 150 Hz decreases. These observations were more identifiable in the S1 spectra than in the S2 spectra, possibly because the S2 higher frequency components may mask subtle changes in the S2 spectra caused by heart size changes. However, when the changes in heart size are significant, as in hypertension or increased body surface area, trends in the S2 spectra can be observed.

Adolescent↗

Mid-systolic sound associated with aortic insufficiency and bisferiens pulse.

Systolic ejection clicks, often associated with cardiac disease, can be distinguished from mid-systolic clicks of mitral and tricuspid origin, which are frequently benign. A different mid-systolic sound has been recognized, with timing similar to the mid-systolic clicks, which is associated with aortic insufficiency. This report describes a case in which such a sound was identified prior to aortic valve replacement, and disappeared with surgery, thus adding evidence to previous concepts of the origin of this sound, and its relationship to the hemodynamic abnormality associated with aortic valvular regurgitation.

Aortic Valve Insufficiency↗

Idiopathic hypertrophic subaortic stenosis as observed in a large community hospital: relation to age and history of hypertension.

The character of idiopathic hypertrophic subaortic stenosis (IHSS) was studied retrospectively in a large community hospital for the six-year period, 1968--1974. Cases were discovered by examining the records of the Cardiac Non-Invasive Laboratory (phono- and echocardiography). Of the 46 cases of IHSS identified, 39 were in patients of the 50--81 age group. Thirty-two (82 percent) of the 39 patients were women, and 25 (78 percent) of these had a significant degree of hypertension. The hypertension had been present for more than five years in 62 percent of the cases. In 84 percent of the elderly females, the cardiac murmur had been present for less than ten years, and in 65 percent for less than five years. There was no family history of IHSS. Eighteen of the 46 IHSS patients underwent cardiac catheterization which confirmed the accuracy of the cardiographic data in all cases. The results of this study indicated that IHSS is usually nonfamilial, predominates in elderly females, and tends to be acquired after a lengthy period of hypertension. Cardiographic data appear highly specific diagnostically, often rendering cardiac catheterization unnecessary. Previous studies have not clearly defined the role of hypertension in the development of IHSS, at least partly because of the highly selective nature of most series reported from referral centers. These series often contain large numbers of younger patients.

Adolescent↗