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Biomedical subjects

S A Kane

Publications and source records attributed to S A Kane.

At least 37 records · Page 2Linked to original sources
PubMed1984

Correlation among right ventricular preload, afterload and ejection fraction in mitral valve disease: radionuclide, echocardiographic and hemodynamic evaluation.

The relation among right ventricular preload, afterload and ejection fraction in patients with mitral valve disease has not been well elucidated. In this study, measurements were made of intracardiac pressures and forward cardiac output during cardiac catheterization (n = 43), the ejection fraction by radionuclide angiography (n = 43) and end-systolic radius and wall thickness by M-mode echocardiography (n = 22). There was a linear correlation between pulmonary artery pressure and right atrial pressure (r = 0.57, p less than 0.01). The right ventricular peak circumferential systolic wall stress was increased in 68% of the patients (in comparison with wall stress measurements obtained in 10 normal subjects). The right ventricular ejection fraction was abnormal in 38 patients (88%) and abnormal in 14 of the 15 patients with high wall stress. There was an inverse correlation between ejection fraction and end-diastolic volume (r = -0.61, p less than 0.001). The right ventricular ejection fraction measurement was repeated within 3 months after mitral valve replacement in 16 patients; the ejection fraction increased from 21 +/- 9 to 29 +/- 10% (mean +/- standard deviation) after surgery (p less than 0.01), but normalization of the ejection fraction was observed in only 3 patients (19%). Thus, abnormal right ventricular ejection fraction, which is observed in most patients with rheumatic mitral valve disease, results from inappropriate wall stress or depressed inotropic response of the right ventricle due to damage. Right ventricular dilation appears to be a compensatory mechanism to maintain the cardiac output.

Aged↗
PubMed1984

Resting kinetics of thallium-201 in patients with coronary artery disease.

The thallium washout was analyzed in 40 patients with angiographically documented CAD, using circumferential time-activity profiles of the initial and four-hour delayed images. A net washout pattern (fewer counts in delayed images than initial images) was observed in the distribution of normal and diseased vessels. A negative washout (wash-in) (a net increase in counts in the four-hour delayed images) was observed only in the presence of diseased vessels, even if the initial scans were normal. Quantitative analysis of thallium kinetics was shown to be important in rest images, and should be performed even if the initial images appear normal.

Adult↗
PubMed1983

Rest and redistribution thallium-201 myocardial scintigraphy to predict improvement in left ventricular function after coronary arterial bypass grafting.

To examine the value of rest and redistribution thallium-201 imaging in predicting improvement in left ventricular (LV) ejection fraction (EF) after coronary artery bypass grafting (CABG), 26 patients with coronary artery disease (CAD) and abnormal LV function were studied. Nineteen patients had pathologic Q waves preoperatively. Rest and redistribution thallium-201 images and radionuclide ventriculograms were obtained before and after CABG, and the thallium scintigrams were evaluated both quantitatively and qualitatively. The patients were divided according to the preoperative thallium scintigrams into 2 groups: Group I (16 patients) had either normal resting thallium-201 images or reversible resting perfusion defects, and Group II (10 patients) had fixed resting perfusion defects. The resting EF was less than 50% preoperatively in all patients. Fourteen patients (54%) showed improvement in EF postoperatively. Three patients (2 in Group I and 1 in Group II) showed new postoperative perfusion defects, and none of the 3 showed improvement in LV function. Of the remaining 14 patients in Group I, 12 (86%) showed improvement in LV function, compared with 2 of 9 patients in Group II (p less than 0.01). Improvement in LV function was observed in 8 of the 19 patients (42%) with abnormal Q waves. Nitroglycerin intervention radionuclide ventriculograms were obtained in 20 patients before CABG. Of the 6 patients who showed improvement in LV function with nitroglycerin, 4 also showed improvement postoperatively. Postoperative improvement in LV function was also observed in 6 of the 14 patients who did not improve with nitroglycerin. Thus, rest and redistribution thallium imaging is useful in identifying patients whose LV function will improve after CABG. Normal rest thallium-201 images or reversible resting defects correctly identified 12 of 14 patients (86%) who showed improvement in LV function postoperatively. Nitroglycerin-intervention ventriculography and abnormal Q waves were less useful in this differentiation.

Adult↗
PubMed1983

Cardiac performance in thyrotoxicosis: analysis of 10 untreated patients.

This study attempts to define cardiac performance at rest and during exercise in patients with untreated thyrotoxicosis. We studied 7 women and 3 men, aged 23 to 59 years (40 +/- 10, mean +/- standard deviation [SD]) and compared the results with those obtained in 12 normal subjects. In patients with thyrotoxicosis, the rhythm was sinus and the only untoward symptom was palpitations; the resting electrocardiographic results were normal in 8 patients and showed left ventricular hypertrophy in 2 patients; the left ventricular ejection fraction and volumes (measured by radionuclide ventriculography) were normal at rest. During exercise, 1 patient had dyspnea and 7 had leg fatigue; 2 were asymptomatic. Also, 7 patients had greater than or equal to 5% increase in left ventricular ejection fraction, 2 had no change, and 1 had a decrease. In all 10 patients, the exercise ejection fraction was greater than or equal to 60%. All normal subjects had a greater than or equal to 5% increase in ejection fraction during exercise. There were no significant differences at rest between patients with thyrotoxicosis and normal subjects in blood pressure, ejection fraction, end-diastolic volume, stroke volume, end-systolic volume, or cardiac output, but the heart rate was significantly higher in patients with thyrotoxicosis (91 +/- 10 versus 80 +/- 12 beats/min, p less than 0.05). During exercise, there were no significant differences between patients with thyrotoxicosis and normal subjects in blood pressure, end-diastolic volume, stroke volume, end-systolic volume, or cardiac output. The exercise ejection fraction was significantly lower in patients with thyrotoxicosis than in normal subjects (68 +/- 10% versus 75 +/- 4%, p less than 0.05). Cardiac performance is normal at rest in patients with thyrotoxicosis, but during exercise abnormal left ventricular reserve occurs in some patients.

Adult↗
PubMed1983

Usefulness of left ventricular wall thickness-to-diameter ratio in thallium-201 scintigraphy.

The ratio of left ventricular wall thickness to the cavity dimension, as seen on thallium-201 images, was used in this study to predict left ventricular ejection fraction and volume. We obtained rest thallium-201 images in 50 patients with symptomatic coronary artery disease. The thickness of a normal-appearing segment of the left ventricular wall and the transverse diameter of the cavity were measured in the left anterior oblique projection. The left ventricular ejection fraction and volume in these patients were determined by radionuclide ventriculography. There was a good correlation between thickness-to-diameter ratio and ejection fraction (r = 0.80) and end-systolic volume (r = -0.71). In 18 patients with a thickness-to-diameter ratio less than 0.70, the ejection fraction was lower than in the 16 patients with thickness-to-diameter ratio greater than or equal to 1.0 (22 +/- 2% versus 49 +/- 3%, mean +/- SEM, p less than 0.001). Similarly, in patients with a thickness-to-diameter ratio less than 0.70, the end-diastolic and end-systolic volume were higher than in the remaining patients with higher thickness-to-diameter ratios (p less than 0.02, p less than 0.001, respectively). All 18 patients with a thickness-to-diameter ratio less than 0.70 had ejection fractions less than 40%; 14 of 15 patients with a thickness-to-diameter ratio greater than or equal to 1.0 had an ejection fraction greater than 40% (p less than 0.001). The remaining 16 patients with a thickness-to-diameter ratio of 0.7-0.99 had intermediate ejection fractions and volumes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Assessment of the myocardial perfusion pattern in patients with multivessel coronary artery disease.

We studied 42 symptomatic patients with coronary artery disease involving two or three vessels using exercise thallium-201 myocardial scintigraphy. Qualitative analysis of the images predicted multivessel disease in 75% of the patients with two-vessel disease and in 82% of the patients with three-vessel disease. Quantitative analysis of the size of the perfusion defect indicated that approximately 40% of the left ventricular perimeter showed abnormal perfusion pattern during stress in these patients, and there was no significant difference in the size of the defect in patients with two-vessel disease or three-vessel disease (41 +/- 17% vs 42 +/- 14%, respectively, mean +/- SD). The exercise heart rate, exercise ECG response, and severity of narrowing did not correlate with the size of the perfusion defect. Patients with anterior infarction had larger defects in the distribution of the left anterior descending artery than those without infarction. Collaterals offered partial protection during exercise only when they were not jeopardized. This study confirms the value of qualitative analysis of exercise thallium-201 imaging in predicting multivessel disease, and describes a simple method of assessing the extent of perfusion abnormalities during stress in patients with multivessel disease. The results may be important in patient management and prognosis.

Adult↗
PubMed1983

Expression of GFAP immunoreactivity during development of long fiber tracts in the rat CNS.

Astrocyte maturation in the developing corpus callosum and dorsal columns of the spinal cord was studied immunocytochemically in the rat, using antiserum to glial fibrillary acidic protein (GFAP) with a view to determining the relationships of astrocytes to the advancing axons of the corpus callosum and corticospinal tract. Between the eighteenth and nineteenth days of gestation, when the corpus callosum commences forming, most of the GFAP staining in the cerebral hemispheres is contained in radial processes, but some staining of glial cell bodies is also seen in the ventricular zone. At the region of interhemispheric fusion, where the corpus callosum will form, an accumulation of astrocytic processes demonstrable electron microscopically shows light immunocytochemical staining for GFAP. These processes do not adopt a stereotyped orientation. Rather, the overall impression as one moves towards the midline, is of radially disposed processes being disrupted and disoriented by the growing callosal axons at the fusion of the hemispheres. At no time can any orderly arrangement of GFAP-containing processes be seen which might indicate that the processes are serving to guide the growing axons across the midline. There is no immunoreactive staining of cell bodies or processes ventral to the corpus callosum, except in postnatal animals. Prior to the arrival of corticospinal axons in the spinal cord on the first postnatal day (PO)21, GFAP immunoreactivity is greatest in radial processes of the lateral funiculi and in the dorsal median septum. Oblique or vertical processes increase in the cuneate fasciculus from P0 tot P4 but do not appear in the gracile fasciculus until P4. Virtually no stained processes appear in the region to be traversed by the principal corticospinal tract, nor later in the tract itself until late in postnatal development. Only by 3 weeks postnatal is the adult pattern of GFAP staining observed in the corticospinal tract. These results also indicate that the expression of GFAP immunoreactivity is a relatively late phenomenon in astrocytes associated with advancing axons and implies that this aspect of astrocytic maturation is unrelated to any guidance that the immature astrocytes might provide for the growing axons.

Animals↗
PubMed1983

Left ventricular function in chronic aortic regurgitation.

Left ventricular performance was determined in 42 patients with moderate or severe aortic regurgitation during upright exercise by measuring left ventricular ejection fraction and volume with radionuclide ventriculography. Classification of the patients according to exercise tolerance showed that patients with normal exercise tolerance (greater than or equal to 7.0 minutes) had a significantly higher ejection fraction at rest (probability [p] = 0.02) and during exercise (p = 0.0002), higher cardiac index at exercise (p = 0.0008) and lower exercise end-systolic volume (p = 0.01) than did patients with limited exercise tolerance. Similar significant differences were noted in younger patients compared with older patients in ejection fraction at rest and exercise (both p = 0.001) and cardiac index at rest (p = 0.03) and exercise (p = 0.0005). The end-diastolic volume decreased during exercise in 60% of the patients. The patients with a decrease in volume were significantly younger and had better exercise tolerance and a larger end-diastolic volume at rest than did patients who showed an increase in volume. The mean corrected left ventricular end-diastolic radius/wall thickness ratio was significantly greater in patients with abnormal than in those with normal exercise reserve (mean +/- standard deviation 476 +/- 146 versus 377 +/- 92 mm Hg, p less than 0.05). Thus, in patients with chronic aortic regurgitation: 1) left ventricular systolic function during exercise was related to age, exercise tolerance and corrected left ventricular end-diastolic radius/wall thickness ratio, and 2) the end-diastolic volume decreased during exercise, especially in younger patients and patients with normal exercise tolerance or a large volume at rest.

Adolescent↗
PubMed1983

Reliability of bedside evaluation in determining left ventricular function: correlation with left ventricular ejection fraction determined by radionuclide ventriculography.

Ninety-nine patients with chronic coronary artery disease were prospectively evaluated to determine the reliability of historical, physical, electrocardiographic and radiologic data in predicting left ventricular ejection fraction. The left ventricular ejection fraction measured by radionuclide angiography was normal (greater than or equal to 50%) in 44 patients (group 1) and abnormal (less than 50%) in 55 patients; 36 of those 55 patients had an ejection fraction between 30 and 49% (group 2) and the remaining 19 patients had an ejection fraction of less than 30% (group 3). The ejection fraction was correctly predicted in 33 of the 44 patients (75%) in group 1 and in 47 of the 55 patients (85%) with abnormal ejection fraction (groups 2 and 3), but the degree of ventricular dysfunction was correctly predicted in only 19 patients (53%) in group 2 and in only 9 patients (47%) in group 3. Stepwise linear regression analysis was performed. The single most predictive variable was cardiomegaly as seen on chest roentgenography (R2 = 0.52). Four optimal predictive variables--cardiomegaly, myocardial infarction as seen on electrocardiography, dyspnea and rales--could explain only 61% of the observed variables in left ventricular ejection fraction. Thus, radionuclide ventriculography adds significantly to the discriminant power of the clinical, radiographic and electrocardiographic characterization of ventricular function in patients with chronic coronary heart disease.

Adult↗
PubMed1983

Value of left ventricular ejection fraction during exercise in predicting the extent of coronary artery disease.

To determine the relation between left ventricular performance during exercise and the extent of coronary artery disease, the results of exercise radionuclide ventriculography were analyzed in 65 patients who also underwent cardiac catheterization. A scoring system was used to quantitate the extent of coronary artery disease. This system takes into account the number and site of stenoses of the major coronary vessels and their secondary branches. The conventional method of interpreting the coronary angiograms indicated that 26 patients had significant coronary artery disease (defined as 70% or more narrowing of luminal diameter) of one vessel, 21 had multivessel disease and 18 had no significant coronary artery disease. Although the exercise left ventricular ejection fraction was significantly higher in patients with no coronary artery disease than in patients with one or multivessel disease (probability [p] less than 0.001), there was considerable overlap among the three groups. With the scoring system, a good correlation was found between the coronary artery disease score and the exercise left ventricular ejection fraction (r = -0.70; p less than 0.001). If the exercise heart rate was 130 beats/min or greater or the age of the patient was 50 years or less, an even better correlation was found (r = -0.73 and r = -0.82, respectively). The exercise ejection fraction (but not the change in ejection fraction, end-diastolic volume and end-systolic volume from rest to exercise) correlated with the extent of coronary artery disease. The exercise ejection fraction is the most important exercise variable that correlates with the extent of coronary artery disease when the latter is assessed quantitatively by a scoring system rather than the conventional method of reporting coronary angiograms. Young age and greater exercise heart rate strengthened the correlation. The change in ejection fraction from rest to exercise is useful in the diagnosis of coronary artery disease, but it was the absolute level of exercise ejection fraction that predicted the extent of disease.

Adult↗
PubMed1983

Effect of oral disopyramide therapy on left ventricular function.

To study the effect of oral disopyramide therapy on left ventricular function, a subject of some controversy, we obtained first-pass radionuclide ventriculograms with a multicrystal gamma camera in 19 patients with or without therapy. Our findings demonstrated that disopyramide causes deterioration in left ventricular function in patients with abnormal ejection fractions. This effect is rarely recognized clinically and occurs despite safe therapeutic serum levels.

Administration, Oral↗