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Biomedical subjects

Robert J. Hall

Publications and source records attributed to Robert J. Hall.

At least 19 recordsLinked to original sources
PubMed1981

The value of electrocardiographic R-wave changes in exercise testing: Preexercise versus postexercise measurements.

To determine the usefulness of R-wave amplitude changes during exercise testing for the diagnosis of coronary artery disease (CAD) and to understand the discrepancies that have been described in the literature regarding their value, we studied two groups of patients by means of electrocardiographic (EKG) treadmill testing and coronary arteriography. Group I was composed of 149 patients who were studied prospectively. The specificity of R-wave changes measured from preexercise to immediately postexercise (SRV(5)) was 81%, but that of R-wave changes measured from preexercise to peak exercise (URV(5)) was 46%. A group of 156 patients (Group II) evaluated retrospectively showed a high specificity for the SRV(5) (84%) and poor specificity for the URV(5) (39%). The sensitivity of the SRV(5) was 38% in Group I and 42% in Group II. Therefore, if measured during the immediate postexercise period and not at peak exercise, changes in R-wave amplitude may be of value in the diagnosis of coronary artery disease by electrocardiographic exercise testing.

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PubMed1981

Calcium antagonists: A new class of therapeutic agents.

A new class of therapeutic agents, sharing inhibition of the slow calcium channel, will soon be available to the American patient. Selective action of these agents upon the atrioventricular node, the smooth muscle of coronary and peripheral arteries, and the contractility of cardiac muscle opens new vistas in cardiovascular pharmacology. Early release of these agents by the Federal Drug Administration for general use is urged, based upon the already wide and successful experience in the European and South American continents.

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PubMed1981

Noninvasive assessment of the stenotic mitral valve orifice by two-dimensional echocardiography.

Two-dimensional echocardiographic imaging of the mitral valve orifice was attempted in 26 patients with isolated mitral stenosis. The intention was to examine further the clinical usefulness and limitations of this technique for estimating the severity of mitral stenosis. Technically adequate recordings of the mitral orifice were obtained in 20 patients (77%). Mitral valve area calculated from echocardiography compared favorably to the valve area derived from cardiac catheterization with the use of the Gorlin formula (r = 0.95). The average difference between the two methods was 0.109 cm(2). Two-dimensional echocardiography does provide clinically useful data for predicting the degree of mitral stenosis in the majority of patients provided that critical technical limitations are recognized.

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PubMed1981

Technique for evaluating left ventricular performance with apical two-dimensional echocardiography: Progress report.

A technique of modelling the left ventricle for the purpose of volume determination has been devised. Two-dimensional echocardiographic data from the apical four chamber and two chamber views are used to pattern the ventricle as a stack of elliptical discs. The method has been validated for an array of regular geometric shapes commonly associated with ventricular architecture. The relative advantages of this model are discussed.

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PubMed1980

Infarct-induced wall motion abnormalities in aortocoronary bypass patients: Correlation with electrocardiographic, enzymatic, and scintigraphic diagnostic criteria.

Gated isotope ventriculograms performed 7 to 12 days postoperatively in 50 aortocoronary bypass patients with perioperative myocardial infarction (POMI) were compared with preoperative contrast ventriculograms. The diagnosis of POMI was based on serial electrocardiograms (EKGs), cardiac enzyme studies, and (99m)Tc-pyrophosphate (PYP) scintigraphy. Seven patients exhibited no new regional wall motion abnormalities. Nine had new areas of localized hypokinesis. The remaining 34 demonstrated localized akinesis or dyskinesis; 12 of these also exhibited a greater than 20% decrease in ejection fraction. The severity of the postoperative wall motion abnormality was paralleled by the intensity of PYP accumulation but not necessarily by the degree of cardiac enzyme elevation. Because they occurred in only 62% of patients, new Q waves were considered an insensitive indicator of POMI. Our study revealed that POMI frequently produces significant changes in left ventricular kinetics. Of the standard techniques utilized, the PYP scan had the greatest predictive value.

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PubMed1980

Two-dimensional echocardiography in the diagnosis of unusual left atrial myxomas.

In two patients with atypical myxomas of the left atrium, two-dimensional echocardiography furnished valuable diagnostic information. In one patient, who had previously developed an embolism at the right brachial artery, M-mode echocardiography revealed an abnormal band of echoes within the left atrium. Two-dimensional echocardiography showed a globular cluster of echoes that remained within the left atrial cavity throughout the cardiac cycle; left ventricular angiography confirmed the ultrasonic findings of an intraatrial mass. At surgery, a calcified, nonprolapsing myxoma was excised from the interatrial septum. The second patient had clinical as well as M-mode echographic features of mitral stenosis. Cardiac catheterization showed a significant gradient across the mitral valve, but the left ventriculogram was normal except for an unusual pattern of mitral regurgitation. Subsequent two-dimensional echocardiography revealed a mass of echoes that prolapsed through the mitral valve during diastole. At surgery, a left atrial myxoma was found attached to the posterior mitral annulus. Our experience indicates that two-dimensional ultrasound is superior to conventional echocardiography for detecting unusual cardiac masses.

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PubMed1980

Left ventricular function early after aortic valve replacement for aortic regurgitation: Assessment by gated radionuclide ventriculography.

This study characterizes left ventricular performance early after aortic valve replacement for severe isolated aortic regurgitation. Gated radionuclide ventriculography studies in 13 patients showed that left ventricular end-diastolic volume was reduced after surgery and that ejection fraction dropped significantly. Despite the fall in ejection fraction, the postoperative cardiac index was significantly greater than the preoperative value. Radionuclide ventriculography is a useful and reliable means of noninvasively assessing left ventricular function soon after aortic valve replacement for aortic regurgitation.

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PubMed1979

ECHO-PHONOCARDIOGRAPHIC CHARACTERISTICS OF THE NORMALLY FUNCTIONING COOLEY-CUTTER MITRAL VALVE PROSTHESIS.

Echocardiographic and phonocardiographic records of 19 patients with a normally functioning Cooley-Cutter mitral valve were analyzed in order to provide quantitative baseline values for this prosthesis. The average duration between the second heart sound and peak opening of the valve (A(2)-OC interval) was 83 +/- 4 (standard error of the mean) msec. The Q-CC interval (from the electrocardiographic Q wave to closure of the valve) was 71 +/- 2 msec. Mean opening and closing velocities of the disc were similar (396 +/- 11 mm/sec and 393 +/- 12 mm/sec, respectively). Amplitude of disc excursion ranged from 6 to 9 mm, but this measurement was not possible in all patients due to the presence of spurious echoes. Early onset of prosthetic valve closure was a relatively common finding in patients with atrial fibrillation or with various forms of atrioventricular block, and frequently resulted in a variety of phonocardiographic alterations. Except for the A(2)-OC interval and amplitude of disc excursion, there was no significant correlation between valve size and echo-phonocardiographic measurements. Results of this study are compared with values previously reported for other types of caged disc valves, and the usefulness and limitations of echo-phonocardiographic assessment of prosthetic valve function are briefly discussed.

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PubMed1978

CROSS-SECTIONAL ECHOCARDIOGRAPHIC FINDINGS IN VEGETATIVE AORTIC VALVE ENDOCARDITIS.

M-mode echocardiograms of two patients with bacterial endocarditis of approximately 4 months' duration showed dense echoes in the area of the aortic valve. In one patient, who had no prior abnormal cardiac findings, the echoes were clearly suggestive of valvular vegetations. The second patient, however, was known to have had aortic valve disease and a systolic murmur for more than a decade; therefore, dense echoes arising from the aortic valve also could have resulted from valvular calcification. In both patients, cross-sectional echocardiography provided important information. In the first patient, retrograde cardiac catheterization was prevented by large and highly mobile masses attached to the aortic cusps that prolapsed into the left ventricular outflow tract during diastole. Aortic valve replacement without further hemodynamic evaluation was recommended. In the second patient, whose blood cultures remained negative after the acute phase of his illness had been treated, cross-sectional echocardiography showed large vegetations on the aortic valve. Intraoperative findings confirmed the echocardiographic interpretation in each case.

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PubMed1978

EXERCISE TESTING AND LEFT MAIN CORONARY ARTERY DISEASE: EXPERIENCE WITH 57 PATIENTS.

Results of multistage treadmill tests (TMT) of 57 patients with critical stenosis (>/= 50%) of the left main coronary artery were analyzed. Additional disease was present in the major vessel in three patients (5%), two vessels in 18 patients (32%), and three vessels in 35 patients (61%). The TMT was negative for ischemia in only two patients (4%), positive in 51 (89%), and undetermined in 4 (7%). TMT was strongly positive (>/= 2 mm ST segment depression) in 40 patients (70%), and in 11 (19%) of these, ST depression was >/= 3 mm. Hypotension with exercise was rare and was encountered in only one patient. Arrhythmias were induced with exercise in six patients (10%) and resulted in premature termination of TMT in four. TMT was terminated due to early ST segment depression in 40 patients (70%), in 17 (30%) without chest pain-an unusual finding. Exercise was limited to stage I (Bruce protocol) in 16 (28%), stage II in 26 (46%), stage III in ten (17%), and stage IV in five (9%). Mean exercise tolerance was 298 +/- 22 seconds (SEM). Maximum heart rate (HR) achieved was 76 +/- 2% of their maximal predicted values. Peak double product (systolic BP x HR) was 20490 +/- 830. The data suggest that the TMT is rarely negative in the presence of LM lesions. An early strongly positive response with or without pain should lead one to suspect LM disease. Exercise-induced hypotension is rare. Limited exercise tolerance and/or early ST segment depression in stages I and II of TMT seem to be predictive of the severity of LM lesions.

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PubMed1978

ACOUSTIC CHANGES IN NORMALLY FUNCTIONING MITRAL VALVE PROSTHESES: ECHO-PHONOCARDIOGRAPHIC OBSERVATIONS.

This study confirms previous findings of variability in the intensity of the closing click (CC) as a consequence of premature valve closure. Such alterations have been described as a normal phenomenon in several prosthetic valve models. Combined echo-phonocardiography is of particular value in evaluating prosthetic valve function in patients with unusual and confusing auscultatory changes.

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PubMed1978

IDENTIFICATION OF LARGE LEFT ATRIAL THROMBUS BY CROSS-SECTIONAL AND M-MODE ECHOCARDIOGRAPHY.

In addition to a typical pattern indicative of mitral stenosis, the M-mode echo-cardiogram of a patient with mitral valve disease revealed a broad band of dense echoes within an enlarged left atrial cavity that was suggestive of an intraatrial thrombus. Subsequent cross-sectional echocardiography demonstrated a globular cluster of echoes inside the left atrial cavity, thus corroborating our interpretation of the M-mode recording. When open mitral commissurotomy was performed, a large, partially calcified thrombus was found protruding from the posterior wall and left atrial appendage into the atrial cavity. Postoperative M-mode and cross-sectional echocardiography did not show the previously noted abnormal echoes within the left atrium.

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PubMed1977

SEVERE PULMONARY HYPERTENSION WITH SIGNIFICANT "A" DIP ON PULMONIC VALVE ECHOCARDIOGRAM.

A patient with severe pulmonary hypertension and no evidence of right ventricular failure who had a 4 mm "a" dip on the pulmonic valve echocardiogram is reported. Although other echocardiographic abnormalities suggesting pulmonary hypertension were recorded in our patient, the normal "a" dip of the pulmonic valve in the absence of right ventricular failure appears to be an exception to previously reported findings. We suggest motion of the entire pulmonary artery as an explanation for this phenomenon.

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