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Biomedical subjects

S W Miller

Publications and source records attributed to S W Miller.

At least 73 records · Page 4Linked to original sources
PubMed1979

Clinical implications of the convex supradiaphragmatic inferior vena cava.

The configuration of the supradiaphragmatic segment of the inferior vena cava (SIVC) was evaluated on lateral chest radiographs to determine the clinical situations in which a posterior convex contour occurred. Of 34 patients with a convex SIVC, 31 had cardiovascular abnormalities. Left ventricular enlargement was present in 17 of 34 (50%), and right ventricular failure in 13 (38%). Valvular regurgitation, left-to-right shunts, narrow anteroposterior chest diameter, and chronic obstructive lung disease were also present. In 102 consecutive normal patients, the SIVC was visible in 97%; only 1 patient had a convex SIVC (p = 10(-7)). The results show that detection of a convex SIVC suggests associated abnormalities.

Adolescent↗
PubMed1979

Evaluation of left ventricular free wall asynergy due to coronary artery disease: use of an interlaced ECG-gated radiography system.

A new radiographic technique produces a high quality image of the chest at end systole and end diastole in a single radiograph. A preliminary study of this method for evaluating various degrees of segmental asynergy of the left ventricular free wall in 25 patients with coronary artery disease showed excellent correlation with left ventriculography (r = 0.88). The method showed a high sensitivity (94%) and specificity (96%). It seems potentially useful to increase the information gained from the chest radiograph in patients with cardiac disease.

Coronary Disease↗
PubMed1979

Noninvasive estimation of pulmonary arterial pressure by analysis of pulmonary blood-flow distribution.

To determine whether a correlation exists between pulmonary arterial (PA) pressure (Pa) and the distribution of pulmonary blood flow, this distribution was measured in four upright dogs in the control state and during intravenous infusions of epinephrine or prostaglandin F2 alpha. During suspension of respiration, 15 mCi of Xe-133 were injected intravenously, and perfusion and equilibration lung images were recorded with a scintillation camera. The procedure was performed several times on each dog, with and without pharmacological elevation of PA pressure by 5 to 50 cm H2O. For each scintigram, the relative blood flow per unit ventilated lung volume (F) was plotted against centimeters above the hilum (h). Pulmonary arterial pressure was derived from each curve, assuming the relation F = B(Pa - hD)2, where B = constant and D = specific gravity of blood. Calculated PA pressure correlated strongly (r = 0.83) with measured PA pressure, suggesting a possible means of noninvasive estimation of PA pressure.

Animals↗
PubMed1978

Coronary, ventricular, and pulmonary abnormalities associated with rupture of the interventricular septum complicating myocardial infarction.

Left ventricular wall motion abnormalities, the extent and location of coronary artery stenoses, and the radiographic evidence of pulmonary venous hypertension were analyzed in a retrospective study of 40 patients who had surgically proven rupture of the interventricular septum after myocardial infarction. In 33 patients in whom chest films were available, interstitial or alveolar pulmonary edema was present in 78%, while left ventricular enlargement was present in 82%. Of 26 patients who had coronary angiography, complete occlusion of the right coronary artery, left anterior descending artery, or left circumflex artery was present in 92%, with few, if any, collateral vessels around the occlusion. The location of the rupture in the muscular septum was always in the region of akinesis or dyskinesis. Posterior defects were associated with posterobasal and diaphragmatic akinesis, and anterior defects with apical akinesis. Left ventricular aneurysms were adjacent to the septal rupture in 68%, and 74% had mitral regurgitation. The right ventricular diaphragmatic wall in posterior rupture was always akinetic, indicating right ventricular infarction. Thus ventricular septal defect after myocardial infarction (1) tends to occur with multiple coronary occlusions about which little collateral flow develops; (2) can accurately be localized anteriorly or posteriorly in the muscular septum by the location of the akinetic left ventricular wall segment; and (3) has an associated right ventricular infarct when rupture is posterior.

Adult↗
PubMed1977

Definition of cardiac structures using computerized tomography in isolated arrested and beating canine hearts.

Computerized axial tomography of the brain is a revolutionary noninvasive technique that has provided remarkable resolution of intracerebral structures. This study was undertaken to determine the potential of computerized tomography for defining the anatomy of 40 arrested and 9 beating (ejecting left heart preparation) canine hearts. Using an EMI cranial unit, scanning was performed in hearts under in vitro conditions with a lactated Ringer's interface. The tomographic scans obtained were later compared with comparable 8 mm thick sections of the heart. At physiologic levels of hematocrit (range 36 to 45%) external structures were well defined, but because of the lack of a differential between cavitary and myocardial densities, it was not possible to distinguish intracardiac structures. With very small amounts of iodinated contrast material (remotely administered in the case of the beating hearts) or with anemia (hematocrit less than 33%), the right and left ventricular cavities became clearly visible in both horizontal and longitudinal tomographic scans. It was possible to distinguish readily the boundaries of the ventricular and atrial cavities, the papillary muscles, the major trabeculae and the aorta. Rhythmic motion of the beating heart, suspended in its pericardium, did not eliminate structural definition. Thus, computerized tomography provides a new approach to the definition of cardiac structure with a relatively high degree of resolution. These observations point to the potential usefulness of this noninvasive technique for the evluation of both cardiac function and ventricular wall abnormalities.

Anemia↗
PubMed1977

Anomalous pulmonary venous connection of entire left lung with intact atrial septum.

Three cases of total unilateral pulmonary venous connection of the left lung with intact atrial septum are described. All patients were acyanotic and had findings of volume overload of the right side of the heart. An anomalous vertical vein in the superior mediastinum and large pulmonary arteries were visible on the plain chest radiograph, similar to what is seen in cases of total anomalous pulmonary venous connection. Selective pulmonary angiography delineated the anomalous connection of the left pulmonary veins and documented the absence of an atrial septal defect.

Adult↗
PubMed1977

Detection of edema associated with myocardial ischemia by computerized tomography in isolated, arrested canine hearts.

This study was undertaken to determine if computerized tomography (CT scanning) with an EMI cranial scanner could detect edema associated with myocardial ischemia in canine hearts. A localized area of decreased density in the posterior papillary muscle and surrounding myocardium was detected on serial 8 mm CT scan slices of each heart after 60 min of circumflex artery occlusion and 45 min of reflow of blood. The wet/dry weight ratios and previous electron microscope studies of the ischemic posterior papillary muscles revealed edema accumulation. After 1 hour of arterial occlusion and 12 hours of reflow (which produces extensive necrosis and a decrease in the wet/dry ratio) lesions were still discernible but were less consistently as severe. Permanent ligation of the left anterior descending coronary artery and major collateral arteries for 6 hours also resulted in a lesion of decreased density in the distribution of the occluded arteries. Thus, CT scanning can detect, and is a potential means for sequential noninvasive quantitation of myocardial edema associated with ischemia.

Animals↗
PubMed1977

Right and left ventricular volumes and wall measurements: determination by computed tomography in arrested canine hearts.

Computed tomographic (CT) images of in vitro hearts filled with iodinated contrast medium have delineated right and left ventricular cavities, papillary muscles, major trabeculae, pulmonary artery, and the aorta. Because of relatively good structural definition, this study was undertaken to determine the potential use of CT in the measurement of cardiac dimensions and cavity volumes. Ten isolated arrested canine hearts were filled with an iodinated oil-paraffin mixture and scanned transversely from base to apex. Measurements of the thickness of the interventricular septum and of the left ventricular posterior wall (indexes of cardiac hypertrophy) had a high degree of correlation to similar measurements of corresponding heart specimens. Using serial tomographic images, the cavity volumes of individual tomographic scans were totaled. The volume of each scan of given thickness was obtained either by the use of planimetry or from a numerical computer printout. Both the planimetric and computer methods gave right and left ventricular volumes which correlated well (P less than .05) with the volumes of paraffin casts. Unlike other techniques widely used for ventricular volume measurement, the method described does not depend on an assumption that the chamber resembles a specific geometric model. This method of volume measurement is applicable to both the left ventricle, regardless of its shape, and to the concave irregularly shaped right ventricle.

Animals↗
PubMed1977

Hepatic cavernous hemangiomas and hemangioendotheliomas in infancy.

Six infants with either cavernous hemangiomas or hemangioendotheliomas of the liver are described. Typical clinical features include cardiac failure, hepatomegaly, and cutaneous hamangiomas. Prompt recognition will direct management to prevent lethal complications of cardiac failure, hyperconsumptive coagulopathy, and hepatic rupture. Dynamic and static hepatic scintigraphy will demonstrate the vascularity and size of the liver mass and provide distinction from other tumors, although in certain circumstances angiography is required.

Angiography↗
PubMed1976

Endotoxin clearance after intralipid infusion.

Healthy 6-8-wk-old New Zealand white rabbits were injected with chromium-chloride- or sodium-chromate-labeled E. coli endotoxin after rapid infusion (10 ml/kg in 1 hr) or slow and repeated infusions (40 ml/kg daily for 7 consecutive days) of 10% Intralipid. Endotoxin clearance rates and RES organ uptakes were determined and the results were compared with those of the controls treated with correspondingly equal volumes of 5% D/W instead of fat. In the acute experiment, the clearance rates were similar in all animals during the first 15 min following endotoxin injection. After this phase, however, experimental animals had faster endotoxin clearance and eventually higher organ uptakes than the controls. In the chronic experiment, there was no significant difference in endotoxin clearance rates or total and per-gram organ uptakes between experimental and corresponding control animals infused with 5% D/W instead of fat. Experimental animals, particularly those having received multiple infusions of fat emulsion, showed deposition of polarizable brown pigment inside and outside the reticuloendothelial cells in the liver, spleen, and bone marrow. None of the controls had these pigments in their organs.

Animals↗
PubMed1976

Interobserver variability in coronary angiography.

Four experienced coronary angiographers (two radiologists and two cardiologists) independently assessed the location and degree of coronary artery stenosis, and the location and degree of left ventricular wall motion abnormalities in 20 coronary angiograms. Marked interobserver variability was noted in quantifying percent coronary artery stenosis and degree of left ventricular wall motion abnormalities. For example, in only 13/20 (65%) of the coronary angiograms did all observers agree about the significance of a stenosis (defined as greater than 50% in diameter luminal narrowing) in the proximal or mid left anterior descending coronary artery. In 3/20 (15%) angiograms there was disagreement by at least one observer about the significance of lesions noted in the main left coronary artery. The ventricle was divided into five segments and the degree of wall motion abnormality graded into six categories of increasing severity from normal to dyskinesis. There was a 42% mean disagreement among all four observers where a disagreement between observers was defined as any difference in grading wall motion abnormalities. Interobserver variability reveals a significant limitation of coronary angiography.

Angiography↗