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T C Gibson

Publications and source records attributed to T C Gibson.

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

Clinical significance of incomplete tricuspid valve closure seen on two-dimensional echocardiography.

Incomplete closure of the tricuspid valve without apparent cusp disease was noted on two-dimensional echocardiography in 31 patients. This abnormality was defined as a failure of the tricuspid valve leaflet tips to reach the plane of the tricuspid valve anulus by at least 1 cm in the standard apical four chamber view at the point of maximal systolic closure. This resulted in a final systolic leaflet position deeper within the right ventricular cavity than is normally seen. The finding was present in the following diagnostic subgroups: Group A, pulmonary hypertension (11 patients); Group B, rheumatic heart disease (4 patients); Group C, dilated cardiomyopathy (9 patients) and Group D, previous myocardial infarction (7 patients). Right atrial, right ventricular and tricuspid anulus measurements were made and compared with those from a group of 67 normal subjects. The results were as follows: right atrial endsystolic area = 27.2 +/- 8.6 cm2 (normal = 13.4 +/- 2.0); right ventricular end-systolic area = 25.6 +/- 8.7 cm2 (normal = 10.9 +/- 2.9); right ventricular end-diastolic area = 31.5 +/- 9.1 cm2 (normal = 20.1 +/- 4.9) and tricuspid valve anular end-systolic dimension = 4.0 +/- 0.6 cm (normal = 2.2 +/- 0.3). The differences from the normal data were all statistically significant (p less than 0.001). Incomplete closure of the tricuspid valve, although a nonspecific diagnostic finding, is primarily associated with right-sided chamber enlargement. Tricuspid regurgitation may be present. The mechanism could be related to geometric changes in valve apparatus dynamics secondary to right-sided cardiac enlargement and tricuspid valve anular dilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Echocardiographic measurement of right ventricular volume.

The volume of the right ventricle can be determined angiographically from its projections in two mutually perpendicular planes. Echocardiographic techniques for measuring right ventricular volume, however, have been more difficult and less successful. In this study, a method was developed for calculating right ventricular volume from two intersecting cross-sectional echocardiographic views: the apical four-chamber and subcostal right ventricular outflow tract views. First, the areas and lengths of casts of 12 human right ventricles obtained at autopsy were directly measured in the chosen views. Actual cast volumes correlated best with a formula giving volume as 2/3 times the area in one view times the long axis in the other view. The degree of correlation was similarly high for calculations involving the area derived from either view and the length of the roughly orthogonal section. This relationship for right ventricular volume was then confirmed with two-dimensional echocardiographic images of hollow latex molds made from the casts (r = .95, p less than .0001). The significance of these findings is discussed in relation to angiographic results and models of the right ventricle.

Adult↗
PubMed1983

Hydrodynamic compression of the right atrium: a new echocardiographic sign of cardiac tamponade.

The relationship of right atrial inversion, a previously undescribed cross-sectional echocardiographic sign, to the presence of cardiac tamponade was examined. We studied 127 patients with moderate or large pericardial effusions. Cardiac tamponade was present in 19 and absent in 104. Four patients with equivocal tamponade were excluded from analysis. Right atrial inversion was present in 19 of 19 patients with cardiac tamponade and 19 of 104 without cardiac tamponade (sensitivity, 100%; specificity, 82%; predictive value, 50%). The degree of inversion as quantitated by the area-corrected curvature did not improve the ability to discriminate between patients with and without cardiac tamponade. However, consideration of the duration of inversion by the right atrial inversion time index (duration of inversion/cardiac cycle length) and an empirically derived cut-off of 0.34 did improve the specificity and predictive value (100% and 100%, respectively) without a significant loss of sensitivity (94%). We conclude that right atrial inversion, particularly if prolonged, is a useful echocardiographic marker of cardiac tamponade that may be of particular diagnostic value when the clinical picture is unclear.

Adolescent↗
PubMed1983

Skull X-rays in minor head injury. A review of their use and interpretation by casualty officers.

A retrospective review of the value of skull X-rays in the management of 1379 patients presenting to an accident and emergency department with minor head injuries was made. Ten skull fractures were identified in this group (an incidence of 0.7%) of which only four were identified by the casualty officer, the remainder being subsequently identified by the radiologist. Some 90 per cent of patients had no history of concussion, and 33 per cent had no external evidence of head injury. All patients with fractures were admitted because of clinical criteria so that skull X-rays played no part in determining whether patients were admitted for observation or not. Only one patient required operative intervention for a compound depressed fracture, and no patient developed an intracranial haematoma. It is concluded that there is need to educate casualty officers on the indications for, and interpretation of skull X-rays. It is hoped that this might decrease the cost to the Health Service of needless skull X-rays, without detriment to the standards of patient care.

Adult↗
PubMed1983

Hyperthyroidism and familial hypertrophic cardiomyopathy.

A kindred with a high incidence of hypertrophic cardiomyopathy (HC) was studied to identify the presence of clinical hyperthyroidism. Two and possibly three members with HC had associated hyperthyroidism. In the propositus, clinical, ECG, and vectorcardiographic evidence for HC resolved after treatment of the hyperthyroidism. We hypothesize that the disproportionately high correlation of hyperthyroidism and HC and the resolution found in the propositus after treatment may indicate that antithyroid therapy should be considered in this form of cardiomyopathy.

Adolescent↗
PubMed1982

Congenital aneurysms of the left atrium: recognition by cross-sectional echocardiography.

The two-dimensional echocardiographic features of three patients with congenital aneurysms of the left atrium are described. The aneurysm arose from the left atrial appendage in two patients and from the posterior left atrial wall in one. The aneurysms were characterized by their origin from an otherwise normal left atrium, a well-defined neck, their position within the pericardial space, and distortion of the left ventricular free wall by the aneurysmal body. The differentiation of these structures from other abnormalities of the left atrium are also discussed. Two-dimensional echocardiography is a safe and reliable method for diagnosing congenital aneurysm of the left atrium, and such studies should be considered in any patient with an otherwise unexplained abnormality on the chest radiograph.

Adult↗
PubMed1982

The effect of amyl nitrite on the mitral valve echocardiogram in presumably healthy young adults.

We analyzed the use of amyl nitrite as a provocative factor in the diagnosis of mitral valve prolapse in a population of healthy young adults. Sixty-five men and 11 women underwent continuous M-mode echocardiographic and phonocardiographic monitoring before, during and after the administration of inhaled amyl nitrite. All of the 76 subjects had normal baseline echocardiograms, and all had a satisfactory hemodynamic response to amyl nitrite. Mitral valve prolapse, defined by echocardiography and phonocardiography, was not provoked in any of the subjects. Therefore, we concluded that, although this technique may be difficult, significant false-positive results should not occur if adherence to strict diagnostic criteria takes place.

Adult↗
PubMed1980

Presumptive tricuspid valve malfunction induced by a pacemaker lead: a case report and review of the literature.

A 23-year-old woman developed 3 degrees AV block with syncope. Insertion of a permanent pacemaker lead was followed by the onset of a persistent murmur in late systole preceded by single or multiple clicks. The murmur was best heard at the left sternal edge, grade 3-4/6 with two major frequencies (60-250 Hz), increased with inspiration and on assuming the erect posture. It was considered to be tricuspid in origin and related to interference of the tricuspid valve apparatus by the pacemaker lead resulting in tricuspid regurgitation. No tricuspid valve prolapse or flutter was seen on echocardiography. Withdrawal of the pacemaker lead resulted in immediate disappearance of the new auscultatory findings. Review of the literature suggests that the appearance of such a murmur following pacemaker insertion could be associated with later complications in relation to tricuspid valve dysfunction. It is therefore recommended that, under these circumstances, permanent pacemaker leads should be appropriately repositioned.

Adult↗
PubMed1978

Blood pressure levels in acute myocardial infarction.

Serial blood pressure recordings were taken for 72 hours in 112 patients with acute myocardial infarction and in 96 patients with cardiac ischemia, admitted to hospital no more than 6 hours after the onset of chest pain. During the first hour of admission 66 (31.7%) had a blood pressure recorded 160/100 or greater. By the sixth hour, without specific antihypertensive therapy, this number had fallen to 13 (6.3%). This fall was subsequently maintained with very similar trends for both acute myocardial infarction and cardiac ischemia. Such an early blood pressure fall in acute myocardial infarction may indicate that this is too labile a measurement to determine the need for, or efficacy of, antihypertensive therapy aimed at the preservation of myocardium. The hospital course and mortality rate of patients with acute myocardial infarction and early hypertension, as defined, did not differ significantly from the non-hypertensive group.

Acute Disease↗
PubMed1977

Primary chylopericardium: the role of lymphangiography.

Primary chylopericardium is often a benign asymoptomatic disease, but patients with associated mediastinal lymphatic tumors may develop cardiac tamponade. Lymphangiography demonstrates mediastinal lymphatic abnormalities in these high risk patients on whom subtotal pericardiectomy and thoracic duct ligation should be performed. Since such tumors have been found in half of reported cases and because extrathoracic lymphangiomas may coexist, lymphangiography with skeletal survey is recommended in all cases. These conclusions are based on a review of 31 published cases and an additional case of our own. Lymphangiographic findings were available in 17 of these patients.

Adolescent↗
PubMed1976

An echocardiographic study of the interventricular septum in constrictive pericarditis.

Ten patients with constrictive pericarditis were studied echocardiographically with specific reference to inter-ventricular septal dynamics. Abnormal movement of the interventricular septum was present in 8 patients and consisted of flattening in systole and unusual posterior motion in diastole. The aetiology of this type of movement is at present unknown but may be related to restriction of normal cardiac rotational dynamics. The interventricular septum also showed diminished degree of thickening (mean 21-2%). The amplitude of excursion was generally at the upper limit of or greater than normal. Left ventricular posterior wall amplitude of excursion was normal. Flattening of left ventricular posterior wall diastolic movement was seen in 4 patients. Right ventricular end-diastolic dimension was slightly increased (1-2 to 1-7 cm/m2) in 5 of 8 patients with abnormal septal motion, but no haemodynamic evidence of diastolic volume overload was found. Posterior pericardial thickening was noted echocardiographically when posterior calcification was present. We conclude that the most common though non-specific feature of the echocardiogram in patients with constrictive pericarditis is abnormal septal motion. Flattening of left ventricular posterior wall diastolic movement, posterior pericardial thickening, and epicardial-pericardial separation may also occur.

Adult↗
PubMed1975

The heart in myasthenia gravis.

The cardiac changes associated with myasthenia gravis have been reviewed and specific areas explored. There is no doubt concerning the involvement of the myocardium in this disease as indicated by clinical, ECG, vectorcardiographic, and autopsy data. The doubt lies in the precipitating factor for the pathology found. On the one hand the whole picture could be a direct result of the pathologic process of myasthenia gravis. On the other hand the patient with myasthenia gravis, during the natural history of the disease, encounters many iatrogenic and coincidental variables which could influence the nature of the clinical findings and autopsy data. One fact seems reasonably clear: The association of myocardial pathology with thymoma, especially malignant thymoma, is well established for the more severe form of the myocardial disease. Furthermore, the hypothesis that cardiac muscle antibodies give rise to such reactions is attractive, although not fully resolved. If such cases are excluded then there remain others where cardiac pathology could be due to other disease, primarily coronary heart disease, in the older group. In addition, the mode of death of some patients indicates that intercurrent respiratory problems could play a part. Most patients in this group do not seem to have cardiac abnormalities due to the pathologic process of myasthenia. There is in addition a small group where very striking cardiovascular findings suggestive of myocarditis are found. There is not necessarily a thymoma and no other specific etiologic factors can be found. These are rare cases and might still be related to disorders of immune mechanisms. In conclusion it can be stated that, although there is now a considerable body of evidence concerning the heart in myasthenia gravis, the implication of specific pathology for this neuromuscular disorder affecting the heart must be considered, in the traditional Scottish legal sense, as "not proven."

Arrhythmias, Cardiac↗
PubMed1975

Interrelationships of insulin, glucose, lipid and anthropometric data in a natural population.

A population sample of 142 men and 148 women aged 40-69 was drawn in Chittenden County, Vermont, and studied for interrelationships among several parameters of obesity, fasting serum cholesterol, triglycerides, glucose and insulin concentrations, and 2-hour post-Glucola glucose and insulin concentrations. No significant sex differences were observed with regard to mean fasting concentrations of glucose, insulin, cholesterol, or triglyceride. Post-Glucola insulin concentrations were higher in women, particularly in the older age groups. Positive correlations were observed between mean log fasting insulin concentration and all parameters of obesity except log triceps skinfold thickness in men. In addition, a positive correlation was present between mean log fasting insulin and fasting triglycerides. There was a positive correlation between fasting triglycerides and ponderal index and estimated percent body fat. Fasting triglycerides correlated with percent ideal weight in women but not in men and with log subscapular skinfold thickness in men but not in women. There was no correlation with either log triceps skinfold thickness or with combined triceps and subscapular skinfold thickness in either men or women. No positive correlations were observed with regard to serum cholesterol. The measurement of glucose and insulin concentrations 2 hours post-Glucola or the calculation of insulin-to-glucose ratios did not provide additional correlations to those observed from the fasting data alone and in some instances correlations which existed in the fasting state were largely obscured following carbohydrate administration.

Adult↗
PubMed1974

Selection for high mutation rates in chemostats.

Competition experiments in chemostats show that mutator populations of Escherichia coli are more fit than wild type. The increased fitness can be explained by the appearance of new mutants better adapted to the chemostat environment. Fitness values vary between chemostats and are strongly correlated (P < 0.001) with fluctuations in population density.

Bacteriological Techniques↗