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Biomedical subjects

C M Gross

Publications and source records attributed to C M Gross.

50 records · Page 3Linked to original sources
PubMed1984

Digital processing of contrast echocardiograms: a new technique for measuring right ventricular ejection fraction.

Imaging of the right ventricle with 2-dimensional echocardiography (2-D echo) is hampered by trabeculation of the right ventricular (RV) endocardial surface and by limited echocardiographic resolution. Determination of RV ejection fraction (EF) is thus often an inconsistent and tedious procedure. The process of digital subtraction contrast echocardiography was developed to maximize echocardiographic definition of the right ventricle and to assess RVEF with minimal operator interaction. Videotaped 2-D echocardiograms recorded during i.v. injection of agitated saline were digitized. Masks were constructed from end-systolic and end-diastolic apical 4-chamber and parasternal RV short-axis images. Masks were subtracted from corresponding images recorded with contrast in the right ventricle; images of the contrast alone were extracted and their areas determined. EF was calculated from raw area measurements and after conversion to volume. Comparison with RVEF measured by first-pass radionuclide angiography yielded the following correlation coefficients: 4-chamber RV area, r = 0.79; parasternal short-axis RV area, r = 0.59; ellipsoid approximation RV volume, r = 0.84; pyramidal RV volume, r = 0.79; and Simpson's rule triangular cylinder RV volume, r = 0.62. Digital subtraction contrast echocardiography is a new method that can be used for semiautomated determination of RVEF. Further studies to assess the clinical values of digital image processing of 2-D echocardiograms to measure RV function appear warranted.

Aged↗
PubMed1984

Model for static lifting: relationship of loads on the spine and the knee.

An experimental study based on a trigonometric, anthropometric model, was conducted on thirty-five healthy subjects to determine the relationship between knee and back forces during symmetric sagittal plane lifting. Total joint reaction forces for the knee and the back, along with their compressive and shear components, were calculated for each subject, as a function of the knee, back and ankle angles. The shear component was significantly higher in females than in males; the compressive component was significantly higher in males. Strong inverse correlations were found between the back and the knee forces on all subjects. Strong correlations were also found between subject anthropometry and minimum and maximum joint reaction forces. The magnitudes of both back and knee joint reaction forces should be considered in recommending the lift type and position, based upon individual worker anthropometry, and size and weight of the load to be lifted.

Adolescent↗
PubMed1984

Stress echocardiography with transesophageal atrial pacing: preliminary report of a new method for detection of ischemic wall motion abnormalities.

We performed two-dimensional echocardiography in 19 patients with significant coronary artery disease and in six normal volunteers at rest and during transesophageal atrial pacing. Technically adequate resting echocardiograms were obtained in 18 of the 19 patients and in all six normal volunteers. In two subjects, atrial capture was not possible, and in one subject, discomfort from the pacing at the beginning of the study precluded its completion. In all subjects (n = 21) who completed the protocol satisfactory two-dimensional echocardiograms were obtained during pacing. Wall motion was normal at rest and during atrial pacing in five normal volunteers. New transient wall motion abnormalities developed in 13 of the 16 patients during pacing. Twelve of the 13 patients had significant coronary lesions in the coronary arteries supplying the abnormal wall segment. Only three of the patients developed significant ST segment depression during pacing. We conclude that stress echocardiography with transesophageal atrial pacing is safe and practical and can be used in patients who cannot perform dynamic exercise, this technique can detect ischemic segmental wall motion abnormalities corresponding to the distribution of coronary arterial obstruction, and the technique provides high-quality echocardiographic images during stress and thus may expand the usefulness of resting two-dimensional echocardiography in patients who have ischemic heart disease.

Aged↗
PubMed1983

Prevalence of mitral prolapse by two dimensional echocardiography in healthy young women.

In order to establish the relative prevalence of mitral valve prolapse as diagnosed by two dimensional echocardiography, we studied 100 presumably healthy young women with two dimensional echocardiography and M-mode echocardiography, history, physical examination, electrocardiography, and phonocardiography. Two dimensional echocardiograms were obtained from parasternal, apical, and subcostal acoustic windows. Mitral valve prolapse was defined as extension of leaflet tissue cephalad to the plane of the mitral annulus into the left atrium; note was also made of any valvular thickening, redundancy, or excessive annular motion. One subject had a midsystolic click and late systolic murmur with evidence of mitral prolapse on both M-mode and two dimensional echocardiography. One subject had a midsystolic click with mitral prolapse demonstrated by two dimensional but not on M-mode echocardiography. One subject had a thick mitral valve on echocardiography but no click or murmur. Four subjects had midsystolic clicks without echocardiographic abnormalities. Mild artefactual pansystolic posterior bowing of the mitral valve on the M-mode echocardiogram could be produced in 20 subjects by incorrect transducer position. We conclude that the prevalence of mitral valve prolapse by two dimensional echocardiography is relatively low in presumably healthy young women. Use of two dimensional echocardiography may avoid overdiagnosis of mitral prolapse and identify a smaller group of individuals with true anatomical abnormalities of the mitral valve.

Adolescent↗
PubMed1981

Two-dimensional echocardiography in the diagnosis of left atrial myxoma.

We performed M-mode echocardiograms on 11 patients who later had left atrial myxomas removed at operations. Seven of these 11 patients were also examined with two-dimensional echocardiography. M-mode echocardiography showed the characteristic pattern of a left atrial mass entering the mitral orifice during diastole in nine of the 11 patients. M-mode echocardiographic findings were equivocal in two patients because a short tumour stalk prevented significant motion of the tumour. Cross-sectional echocardiography clearly showed a left atrial mass attached by a stalk to the interatrial septum in all seven patients examined, including one patient in whom the tumour was immobile. Three-dimensional measurements of tumour size made from orthogonal cross-sectional echocardiographic planes were within 6 mm of similar measurements made on the excised tumours.

Adolescent↗
PubMed1979

Mitral valve prolapse in the elderly.

This study included 40 patients over 60 years of age with echocardiographic findings of mitral valve prolapse (MVP). Most of these patients were unaware of any cardiac disorder until the time of echocardiography. In the majority, the clinical manifestations were benign, and the duration of symptoms variable. Congestive heart failure (CHF) was noted in 10 patients (25 percent) who were unaware of having any cardiac disorders until the onset of their symptoms. In 5 patients (4 with CHF and 1 with endocarditis), surgical replacement of the prolapsed mitral valve was necessary. Endocarditis was present in 4 patients (10 percent), none of whom had been instructed in the prophylactic use of antibiotics. The physician's awareness of mitral valve prolapse in the elderly patient is important, since the disorder may not be as benign in aged patients as in younger ones, and life-threatening complications may occur.

Aged↗
PubMed1979

Infected left atrial myxoma with bacteremia simulating infective endocarditis.

A 58-year-old man had intermittent fever of eight months' duration following a dental extraction. There were no abnormal cardiac auscultatory findings. Multiple blood cultures yielded Streptococcus mutans. Treatment for infective endocarditis was initiated; however, an echocardiogram suggested the presence of a left atrial myxoma. The diagnosis was confirmed by angiography and the infected tumor was removed successfully. Differentiating features between left atrial myxoma and mitral valve endocarditis may not be obvious clinically, and bacteremia does not preclude atrial myxoma as a diagnostic possibility. We therefore suggest that all cases of infective endocarditis be evaluated by echocardiography to elucidate lesions such as large vegetations or left atrial myxoma, both of which may require urgent operative intervention.

Diagnosis, Differential↗
PubMed1976

Echocardiographic studies of abnormalities associated with coarctation of the aorta.

Echocardiograms were performed in thirty-six patients (aged 4 to 36 years) with proven coarctation of the aorta. Nineteen patients (53%) were found to have marked diastolic eccentricities of their aortic valves (Eccentricity Index greater 1.5), indicating the presence of bicuspid aortic valves. One of these patients also had multilayered aortic root echoes in diastole. Five patients had angiographic proof of their aortic valve morphologies which corroborated the echo findings. Five patients with bicuspid aortic valves showed mitral valve diastolic flutter indicative of aortic regurgitation. Idiopathic hypertrophic subaortic stenosis (IHSS) was suspected in four patients (11%) with abnormal systolic anterior motion of the mitral valve; three of these patients also had asymmetric septal hypertrophy. There was catheterization proof of IHSS in one patient. Two patients (5.6%) demonstrated mitral valve proplapse.

Amyl Nitrite↗
PubMed1976

Echocardiography of cardiac valves in pericardial effusion.

Nine adult patients with large pericardial effusions (PE) demonstrated echocardiographic motion abnormalites of cardiac valves in systole. In four cases (Group 1), the abnormal findings consisted of prominent systolic anterior movements of the mitral valve resembling those seen in idiopathic hypertrophic subaortic stenosis. In Group 2(five cases), typical mitral valve prolapse patterns with large posterior midsystolic displacements well below the C point were observed. Additional abnormalities in Group 2 included tricuspid valve prolapse patterns (four cases), early systolic movement of the aortic valve toward closure (three cases), midsystolic notching of the pulmonary valve (two cases) and abnormal or attenuated motion of the aortic root in all patients. Marked decrease or resolution of PE resulted in complete disappearance of all the observed abnormalities. These findings appeared to be related to large fluid collections behind the left atrium and abnormal movement of the heart in the pericardial space. In the presence of PE, therefore, the echocardiographic observation of abnormal valve motion may not be clinically significant.

Adult↗
PubMedDate not supplied

Mitral valve prolapse and stroke: echocardiographic evidence for a missing causative link.

There is general acceptance of a causal connection between mitral valve prolapse and systemic embolic events. The precise mechanism, however, remains controversial, with current hypotheses favoring the embolization of thrombotic deposits from the abnormal mitral valve. It might be surmised that echocardiography could easily document the presence of such thrombi, but actually, this has never been reported previously. Described herein is a patient with a severe cerebrovascular accident in whom echocardiography clearly demonstrated a mass of high embolic potential attached directly to the prolapsing mitral valve leaflet.

Adult↗