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Biomedical subjects

G Glick

Publications and source records attributed to G Glick.

At least 19 recordsLinked to original sources
PubMed1979

The superiority of mitral E point-ventricular septum separation to other echocardiographic indicators of left ventricular performance.

M-mode echocardiography, angiocardiography, and coronary arteriography were done in 40 patients with coronary heart disease, 12 with congestive cardiomyopathy, and 14 with no detectable cardiac or coronary abnormality. We measured mitral E point-ventricular septum separation (EPSS) at the moment of the E peak; the previously described method measures EPSS as the vertical distance between the nadir of systolic septal motion and the subsequent mitral E peak. Angiocardiographic ejection fractions correlated better with EPSS (r = 0.83) than with left ventricular (LV) end-diastolic internal diameter (r = 0.62), LV internal diameter systolic shortening fraction (r = 0.64), LV echocardiographic ejection fraction (r = 0.70), and LV posterior wall systolic thickening (r = 0.58). Patients with angiocardiographic ejection fractions below 55% usually had EPSS values over 10 mm by our method. Six false negatives and one false positive occurred. Our observations in patients with impaired LV performance suggest that LV dilatation, and especially dilatation of the LV outflow tract, is relatively more important than reduction in the amplitude of diastolic anterior mitral excursion in the production of high EPSS values. Although the usual method for measuring EPSS and ours are equally satisfactory, ours has certain theoretical advantages.

Adult↗
PubMed1979

Submitral calcification or sclerosis in elderly patients: M mode and two dimensional echocardiography in "mitral anulus calcification".

Submitral calcification or sclerosis was visualized with M mode echocardiography in 84 elderly patients, 35 of whom were also studied with two dimensional echocardiography. Posterior submitral calcification, commonly referred to as "mitral anulus calcification," was present in 82 patients and was located in the angle between the posterior mitral leaflet and left ventricular posterior wall, rather than in the mitral anulus proper. M mode scans from the left ventricle to the left atrium showed that posterior submitral calcification ended abruptly in 66 cases, and in these it became contiguous with the posterior atrioventricular junction (true mitral anulus) in only 14 instances, in 16 patients the posterior submitral calcification sloped anteriorly to merge with the posterior aortic root. Anterior submitral calcification was visualized in 12 patients, 10 of whom also had posterior submitral calcification. Anterior submitral calcification was usually located immediately anterior to the base of the anterior mitral cusp. In two cases, if appeared to arise in the region between the aortic and mitral rings; in one instance, it was located in the mid left ventricle, in the mitral chordal region. We suggest that the terms anterior and posterior submitral calcification are more appropriate than "mitral anulus calcification" because in most cases such calcific deposits do not appear to be located in or to arise from the true mitral anulus.

Age Factors↗
PubMed1979

Effects of hypertonic mannitol on cardiac lymph in nonischemic myocardium.

This investigation was designed to elucidate the effects of hypertonic mannitol on the nonischemic myocardium. In anesthetized open-chest dogs, we collected cardiac lymph for 2 h before and for 4 h during the infusion of hypertonic mannitol or normal saline. We studied the changes in the volume of lymph flow and the release of lysosomal enzyme acid phosphatase and protein into the cardiac lymph. In group 1 (n = 7) and group 3 (n = 8), the effects of 1-h and 4-h infusions of mannitol were studied, respectively. In these dogs, mannitol caused significant rises in lymph flow and release of total acid phosphatase into the cardiac lymph. In group 3, protein efflux increased significantly. In group 2 (n = 5) and group 4 (n = 4), infusion of normal saline for 1 and 4 h did not significantly change the release of total acid phosphatase and proteins into the cardiac lymph. Thus, infusion of hypertonic mannitol for 1--4 h in the nonischemic myocardium may have some deleterious effects because of its apparent ability to impair lysosomal membranes and to increase capillary permeability.

Acid Phosphatase↗
PubMed1979

A perfused canine right bundle branch-septal model for electrophysiological studies.

UNLABELLED: As documented in the literature, isolated ventricular muscle preparations perfused with protein-free media become edematous and deteriorate. We hypothesized that the addition of colloid oncotic pressure to the perfusion medium might affect favorably the electrical characteristics and survival of an isolated right bundle branch-septal muscle preparation perfused via the anterior septal artery. Perfusion with protein-free Tyrode solution produced edema formation and a loss of transmembrane potential of Purkinje and muscle cells within 5.9 +/- 0.40 h. Addition of bovine albumin, 4 g/100 ml, to the Tyrode solution or perfusion with horse serum greatly reduced the formation of edema. Furthermore, intact electrical activity continued for more than 9 +/- 0.31 h (P less than 0.001). The preparations showed a greater diastolic potential and action potential amplitude during perfusion than during superfusion with Tyrode solution. IN CONCLUSION: 1) a viable, perfused septal muscle preparation was developed for electrophysiological studies, and 2) colloid oncotic pressure in the perfusion medium is essential to preserve the integrity of the capillary circulation and to eliminate edema formation and tissue death.

Animals↗
PubMed1979

Aspirin inhibits development of coronary atherosclerosis in cynomolgus monkeys (Macaca fascicularis) fed an atherogenic diet.

The effect of aspirin in the primary prevention of diet-induced atherogenesis in cynomolgus monkeys was studied. The diet consisted of 2% cholesterol and 10% butter by weight for 24 wk. Six monkeys received only the atherogenic diet and five monkeys received the diet plus aspirin, 81 mg/monkey per day. Aspirin did not affect plasma cholesterol levels or aortic atherosclerosis. Platelet aggregation to arachidonic acid was almost completely suppressed. Aspirin decreased significantly the number of coronary vessels with atherosclerotic involvement, and the number of coronary vessels narrowed by 20% or more. Thus, aspirin appears to exert a protective effect in the primary prevention of diet-induced coronary atherosclerosis in a primate model.

Animals↗
PubMed1979

Effects of veratrine on the in situ dog heart: evidence for increased ventricular fibrillation threshold.

The present work studied the effect of veratrine on electrical stability of the mammalian ventricles. In a group of anesthetized open-chest dogs we determined the effects of veratrine (0.001-0.3 mg/kg) on the threshold for ventricular fibrillation (VFT), both during sinus rhythm (SR) and during atrial drive (AD) at 166 +/- 7 beats/min. Veratrine (0.3 mg/kg) increased the VFT during SR from control levels of 33 +/- 5 mA to 56 +/- 4 mA (P less than .05) and during AD from 34 +/- 6 to 57 +/- 9 mA (P less than .05). VFTs after infusion of veratrine were higher than in a control group of dogs given the saline diluent in which VFT during SR was 26 +/- 3 mA (P less than .001) and during AD was 24 +/- 3 mA (P less than .005). The increase in VFT during SR was independent of the decrease in heart rate, which fell from 147 +/- 8 to 106 +/- 6 beats/min (P less than .001). It was associated, however, with an increase in the QT interval during SR from control values of 254 +/- 13 to 308 +/- 19 msec (P less than .02) and during AD from 238 +/- 8 to 267 +/- 8 msec (P less than .005). We conclude that small doses of veratrine increase the electrical stability of the ventricles in the normal dog heart.

Animals↗
PubMed1978

Successful treatment of drug-resistant atrial tachycardia and intractable congestive heart failure with permanent coupled atrial pacing.

Temporary coupled atrial stimulation slowed the ventricular rate by nearly 50% in an adolescent patient with intractable congestive heart failure and focal repetitive atrial tachycardia that was resistant to drug treatment. Because of the success with the temporary pacemaker, a specially designed permanent pacemaker was implanted to provide coupled atrial stimulation. The necessary electrophysiologic conditions for ventricular slowing by coupled atrial pacing are: (1) an atrial effective refractory period shorter than that of the atrioventricular junction, and (2) depolarization of the ectopic atrial pacemaker by the responses to coupled atrial stimulation. During a 4 year follow-up period the treatment resulted in elimination of the tachycardia, followed by return of the heart size to normal and complete clinical recovery. Coupled atrial stimulation can provide effective treatment in selected patients with disabling drug-resistant atrial tachycardia in whom this mode of therapy is shown to be effective by careful electrophysiologic studies.

Adolescent↗
PubMed1978

Diet-induced atherosclerosis and experimental hypertension in stumptail macaques (Macaca arctoides). Effects of antihypertensive drugs and a non-atherogenic diet in the evolution of lesions.

This study was carried out to determine the evolution of atherosclerotic lesions during a therapeutic period during which regression might be appreciated. We produced aortic and coronary atherosclerosis in 27 young adult stumptail macaques (Macaca arctoides) by feeding a diet supplemented with 2% cholesterol and 25% fat. Hypertension was produced by bilateral or unilateral narrowing of the renal artery. After six months of this regimen, four monkeys were killed (group 1) and 23 monkeys were divided into three groups: group 2 received unsupplemented diet; group 3 received the same diet as group 2 and drug treatment for hypertension; group 4 was continued on the atherogenic diet and received antihypertensive drug treatment. The results indicate that deleting the atherogenic diet leads to a decrease in the lipid content of the lesions and a transformation of the lipid laden atherosclerotic plaques into lipid-poor, fibro-collagenous lesions, with a decrease in the amount of coronary luminal narrowing. Partial control of systolic hypertension by antihypertensive drugs did not accelerate the involution of the atherosclerotic lesions over the relatively short period of this study. No statistically significant correlation by regression analysis was observed between the level of blood pressure elevation, the plasma renin activity, or the degree of the drug response, and the severity and extent of the atherosclerotic lesions. Furthermore, severe arterial hypertension without an atherogenic diet (group 5) produced arteriosclerosis of the aorta, and intensified branch cushions in the coronary arteries, without inducing lipid deposition in either vascular bed.

Animals↗
PubMed1978

Echocardiographic diagnosis of dilatation of the ascending aorta using right parasternal scanning.

With the ultrasound transducer positioned at the second or third right intercostal space, the ascending aorta was visualized in 8 patients in whom dilatation of the ascending aorta had been demonstrated radiographically. The diameter of the ascending aorta by right parasternal scan, with the transducer held perpendicular to the chest wall, measured 4.2-6 cm. The aortic root diameter (at aortic valve level) recorded by conventional left parasternal scan was normal or only slightly increased in 5 cases, but in 3 others it approached the value obtained by right parasternal scan. Aortography performed in 3 patients demonstrated marked dilatation of the ascending aorta.

Adult↗
PubMed1978

Echocardiographic detection of cardiac involvement in patients with chronic renal failure.

Echocardiography was performed in 50 patients in chronic renal failure with symptoms suggestive of possible cardiac involvement. Pericardial effusions were detected in 33 and pericardial thickening in 22. In five patients solid material, probably fibrinous, was seen adherent to the parietal or visceral pericardium. The left ventricle was dilated in 18 patients and showed definitely impaired contractility in 16. The left ventricular (LV) posterior wall was abnormally thick in 19 patients. In two, the ventricular septum was more than 1.3 times as thick as the LV posterior wall. Other echocardiographic findings included calcification in the mitral annulus region, mitral valve vegetations, and thickened chordae tendineae. Echocardiography has proved to be of great help in the assessment of symptomatic patients with chronic renal failure not only in diagnosing the presence and extent of pericardial effusion and thickening, but also in detecting impaired myocardial contractility, calcification in the posterior mitral annulus region, and vegetations of bacterial endocarditis.

Adolescent↗
PubMed1977

Effects of propranolol, minoxidil, and clofibrate on cholesterol-induced atherosclerosis in stumptail macaques (Macaca arctoides).

Propanolol, minoxidil, and clofibrate, three different classes of pharmacological agents used clinically in various conditions related to atherosclerosis, were shown not to have any intrinsic potentiating effects on the development of atherosclerosis in stumptail macaques fed an atherogenic diet. We did obtain, however, some results that suggest that clofibrate and propranolol may exert some beneficial actions.

Animals↗
PubMed1977

Attenuation of cardiac sympathetic drive in experimental myocardial ischemia in dogs.

Sympathetic discharges to the heart were recorded from the left inferior cardiac nerve of 16 dogs. Inferior cardiac nerve activity (ICNA) under normal conditions consisted of grouped discharges, synchronous with the cardiac cycle and modulated by respiration. After ligation of the circumflex branch of the left coronary artery, ICNA declined concomitant with a decline in heart rate and mean aortic pressure. After 30 minutes, when arterial pressure tended to recover toward control values (six dogs), ICNA remained low; in contrast, when arterial pressure dropped to shock levels (three dogs), ICNA increaed. When aortic pressure fell precipitously as a result of ventricular fibrillation, even during the first 30 minutes of ischemia (seven dogs), ICNA immediately increased greatly. The results of this study suggest that acute coronary occlusion produces a cardiocardiac depressor reflex with attenuation of sympathetic discharge to the heart. This reflex, under the experimental conditions studied, gives way to the baroreceptor reflex when aortic pressure drops to critically low levels.

Animals↗
PubMed1977

Potential pitfalls in quantification of pericardial effusions by echocardiography.

In the echocardiographic assessment of patients with pericardial effusions, the apparent width of the echo-free space between the left ventricular posterior wall and the parietal pericardium is commonly used to estimate the amount of pericardial fluid present. In 4 patients with pericardial effusions, we showed a distinct disparity between the widths of the posterior pericardial space at different levels of the left ventricular posterior wall. In 2 of them, a 'swinging heart' appearance was recorded when the ultrasoound beam was directed caudally, but not when its direction was cephalad or less caudad. It is suggested that the left ventricle should be scanned at all possible sites to minimise potential errors in estimating the amount of a pericardial effusion.

Adult↗
PubMed1977

Effects of methylprednisolone on cardiac lymph in acute myocardial ischemia in dogs.

It has been proposed that administration of pharmacologic doses of glucocorticoids may be beneficial in the setting of acute myocardial ischemia because of their ability to stabilize lysosomal membranes and thereby to prevent the leakage of proteolytic enzymes into the cytoplasm and interstitium. We collected cardiac lymph in anesthetized open-chest dogs in successive 2-h periods and used acid phosphatase as our marker lysosomal enzyme. In group 1 (n=5), we studied the effect of time alone. In these dogs, the total amount of acid phosphatase decreased (P less than 0.05). In group 2 (n=5), methylprednisolone, 30 mg/kg iv, was given. This drug did not change any variable we measured. Ligation of the circumflex coronary artery in group 3 (n=7), produced a significant increase (P less than 0.05) in the amount of acid phosphatase drained from the heart compared to group 1. In the dogs of group 4 (n=5), methylprednisolone did not reduce, and may have augmented, the total amount of acid phosphatase draining from the heart. Thus glucocorticoids do not appear to reduce the amount of acid phosphatase released by the ischemic myocardium into the cardiac lymph.

Acid Phosphatase↗
PubMed1977

Echocardiographic features of second degree atrioventricular block.

Echocardiographic studies demonstrated abnormalities of motion of the pulmonary valve, the aortic root and valve, the mitral and tricuspid valves, the left ventricle, and the left atrium in two patients with second-degree atrioventricular block. During Wenckebach 3:2 atrioventricular conduction, ventricular beats exhibited alternately long and short periods of systolic opening of the pulmonary and aortic valves and alternately large and small left ventricular stroke volumes. During 4:3 and 3:2 Wenckebach atrioventricular conduction, the left ventricular stroke volume was directly proportional to the preceding end-diastolic volume. During 2:1 atrioventricular conduction, the blocked atrial contractions may produce movements of the left atrial wall, thereby revealing the true atrial rate when the blocked P waves are obscured in the electrocardiogram by their superimposition on preceding T waves.

Adolescent↗