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Biomedical subjects

R J Hall

Publications and source records attributed to R J Hall.

At least 145 records · Page 8Linked to original sources
PubMed1983

Left ventricular performance during exercise in patients with left bundle branch block: evaluation by gated radionuclide ventriculography.

To investigate changes in left ventricular (LV) function during exercise in patients with left bundle branch block (LBBB), 22 patients without a history or physical findings of previous myocardial infarction or LV dysfunction were studied by gated radionuclide ventriculography (GRNV) at rest and during bicycle exercise. Coronary arteriography demonstrated greater than 75% diameter narrowing of at least one coronary artery in nine patients. Of the remaining 13 patients, GRNV demonstrated wall motion abnormalities in seven patients either at rest or with exercise. During exercise, mean ejection fraction (EF) did not increase in patients without coronary artery disease (CAD). Patients with CAD had a 12-point fall in mean EF with exercise. We conclude that LV reserve, as demonstrated by ability to increase EF with exercise, is impaired in patients with LBBB even in the absence of CAD or other underlying cardiac disease and that standard GRNV criteria to exclude the presence of CAD (a greater than five-point increase in EF with exercise and normal wall motion) are not strictly applicable in screening patients with LBBB.

Adult↗
PubMed1983

M-mode echocardiography in the detection of surgically resectable left ventricular aneurysm.

Thirty-nine patients with severe cardiac failure and a previous transmural myocardial infarct were studied prospectively to assess the ability of M-mode echocardiography to detect resectable left ventricular aneurysms. Subsequent angiography showed an aneurysm in 23 patients and diffuse left ventricular damage in 16. Nine (57%) of the patients without aneurysm had either left ventricular end-systolic dimensions in excess of 6 cm combined with reduced contraction of the base of the left ventricle (fractional shortening of the level of the mitral valve less than 20%), or gross reduction of contraction (fractional shortening less than 15%) regardless of left ventricular dimension. These abnormalities did not occur in any patient with an aneurysm. In 21 (91%) of the patients with a left ventricular aneurysm its presence was correctly predicted either by fractional shortening in excess of 20% (16 patients) or gross delay of mitral valve opening (greater than 80 ms 16 patients). In one patient without an aneurysm, fractional shortening was greater than 20% and thus incorrectly suggested the presence of aneurysm. Only 39% of aneurysms were directly visualized. Therefore M-mode echocardiography can correctly rule out the diagnosis in over 50% of patients without an aneurysm and strongly suggest the possibility in over 90% of patients with one.

Adult↗
PubMed1983

Kinetics of two subgroups of propionate-using organisms in anaerobic digestion.

A novel method for measuring the kinetics of a subgroup of organisms growing in mixed culture was used to measure the kinetics of propionate-using organisms in a mixed-population anaerobic digester. It was shown that there are at least two subgroups of propionate-using organisms with distinctly different growth kinetics. Both subgroups could grow without reducing sulfate. The slower-growing subgroup had a Ks of 11 mg/liter and a mumax of 0.0054 h-1 which is similar to the mumax reported for Syntrophobacter wolinii. The faster-growing group had a mumax of 0.050 h-1 and a Ks of 330 mg/liter. The slower-growing group was inhibited by a pH shock from 7.0 to 6.0, whereas the faster-growing group was less sensitive to the pH shock.

Bacteria, Anaerobic↗
PubMed1983

Subacute massive pulmonary embolism treated with plasminogen and streptokinase.

Major pulmonary embolism occurring insidiously over several weeks (subacute massive pulmonary embolism) has a high mortality and may not respond well to standard anticoagulant or thrombolytic treatment. A priming dose of plasminogen was used to enhance thrombolysis produced by a streptokinase infusion in five consecutive patients with subacute massive pulmonary embolism. In each patient a dramatic clinical improvement occurred with a substantial increase in pulmonary blood flow. All five patients survived to leave hospital. Malignant disease was the underlying cause of embolism in three patients, two of whom died of their malignant disease in the six months after treatment of their pulmonary embolism. The third patient with malignant disease had a choriocarcinoma; at least some of the pulmonary obstruction may have been tumour tissue but this obstruction was dramatically cleared by the treatment. The use of a combination of plasminogen with streptokinase should be considered in severely ill patients with subacute massive pulmonary embolism, particularly if other treatment, including streptokinase alone, has failed.

Adult↗
PubMed1983

Residues of petroleum hydrocarbons in tissues of sea turtles exposed to the Ixtoc I oil spill.

Sea turtles found dead when the Ixtoc I oil spill reached Texas waters were necropsied and tissues were analyzed for residues of petroleum hydrocarbons. Two of three turtles were in poor flesh, but had no apparent oil-caused lesions. There was evidence of oil in all tissues examined and indications that the exposure had been chronic. Comparisons with results of studies done on birds indicate consumption of 50,000 ppm or more of oil in the diet. Some possible mechanisms of mortality are suggested.

Animals↗
PubMed1983

Exercise-induced right ventricular tachycardia and arrhythmogenic right ventricular dysplasia: electrophysiologic and therapeutic considerations.

Three cases of exercise-induced ventricular tachycardia with associated right ventricular dysplasia are described. In each case, patients experienced ventricular tachycardia during treadmill tests. In all three patients, echocardiography or nuclear scintigraphy revealed a dilated right ventricle with reduced ejection fraction; cardiac catheterization with angiography also showed a dilated and hypokinetic right ventricle in each case. Two patients underwent electrophysiology studies that showed an inducible ventricular tachycardia originating from the right ventricular outflow tract. All three patients were treated with single agent antiarrhythmic drugs that controlled their ventricular tachycardia.

Journal Article↗
PubMed1983

Right ventricular thrombus: clinical and diagnostic features.

Because of clinical symptoms and findings at physical, echocardiographic, and angiographic examination, a patient was suspected of having a tumor in the right ventricle. Results of surgical and pathological examination, however, revealed a thrombus obliterating the right ventricle. The purpose of this article is to delineate the features of a patient with right ventricular thrombus.

Journal Article↗
PubMed1983

Congestive cardiomyopathy presumably secondary to oxacillin.

A patient developed congestive cardiomyopathy after a long-term course of oxacillin. When the drug was discontinued, cardiac function returned to normal. The summary of clinical findings strongly suggested a cause-and-effect relationship between the intake of oxacillin and the deterioration in myocardial contractility.

Journal Article↗
PubMed1983

Takayasu's arteritis: diagnostic considerations and surgical treatment.

A 20-year-old white woman with Takayasu's arteritis had headaches, neck soreness, and a right carotid bruit. Corticosteroid treatment only temporarily relieved symptoms and caused Cushing's syndrome because of high dosage requirements. Progressive narrowing of the right common carotid artery occurred despite treatment. The diseased portion of the artery was successfully resected and replaced by a Dacron graft. Corticosteroid treatment was then tapered and discontinued, and the patient has remained well for 3 years. Carotid Doppler and real-time ultrasound studies performed more than 2 years after surgery showed a patent graft and no new disease process. This technique may be of value in selected cases for both prevention of cerebral ischemia and the elimination of local symptoms of the inflammatory process.

Journal Article↗
PubMed1983

Unusual combination of total occlusion of left main coronary artery and heart failure with pulmonary hemosiderosis: case report.

A case of total occlusion of the left main coronary artery, congestive heart failure, and pulmonary hemosiderosis in a 54-year-old man is reported. Cardiac catheterization showed total occlusion of the left main coronary artery, subtotal occlusion of the right coronary artery, severely deranged hemodynamics, and an akinetic left ventricle except for a hypokinetic posterobasal segment. A radionuclide left ventricular performance study revealed an ejection fraction of 0.16 with diffuse biventricular hypokinesis and dilatation. Despite all the risk factors, the patient underwent a total of six saphenous vein grafts without perioperative or immediate postoperative complications.

Journal Article↗
PubMed1983

Clinical utility of a two-site immunoradiometric assay for creatine kinase-MB in the detection of perioperative myocardial infarction.

In 144 patients, creatine kinase MB was measured serially at 0, 8, 16, 24, 48, and 72 hr using a two-site immunoradiometric assay (IRMA). Cardiac enzymes were also measured, including SGOT, LDH, total CPK, and CK-MB by electrophoresis. The presence of perioperative myocardial infarction (poMI) was established in 24 patients by the appearance of new electrocardiographic Q waves and/or new wall motion abnormalities detected by radionuclide ventriculography. In patients without poMI, CK-MB (IRMA) was elevated (6.4 +/- 4.9 equivalent units per liter) at 0-8 hr but decreased to 3.4 +/- 1.3 EU/l by 16 hr. In patients with poMI, peak values occurred at 16-24 hr (21.0 +/- 19.8 EU/l). Using a threshold value of 8.5 EU/l, patients with poMI could be distinguished from those without with 97% accuracy (sensitivity = 88%, specificity = 99%). The CK-MB (IRMA) was more reliable than the other enzyme assays, for which we used both empirically elevated threshold values based upon previous experience, and also threshold values retrospectively optimized for the study population. We conclude that the CK-MB (IRMA) can serve as a valuable postoperative screening test for poMI.

Aspartate Aminotransferases↗
PubMed1982

Premature closure of prosthetic mitral valves as a consequence of gravity.

To determine the influence of gravity on premature closure of prosthetic mitral valves, we studied 17 patients in whom this phenomenon had been observed during routine examination. All patients were in atrial fibrillation and none had aortic incompetence. Patients were studied in multiple positions by means of simultaneous echocardiography, phonocardiography, and cinefluoroscopy. In all patients premature closure was observed when the atrial side of the prosthesis was below the ventricular side, resulting in a downward motion of the occluder inside the valve cage. When patients were studied in positions in which the atrial side of the valve was higher that the ventricular side, premature closure never occurred, even during extremely prolonged diastolic periods. Since minor positional changes, which were found to determine whether premature closure occurred or not, are unlikely to produce significant alterations in pressure and flow across the mitral orifice during diastole, we conclude that position-dependent premature closure of prosthetic mitral valves in patients with atrial fibrillation is best explained by the effect of gravity on the prosthetic occluder. Examination of such patients in multiple positions should be helpful in distinguishing premature valve closure caused by aortic regurgitation from gravity-related presystolic closure. Inability to produce premature closure in patients in whom it had previously been demonstrated in the presence of similar R-R intervals may even prove useful in diagnosing new orifice obstruction.

Atrial Fibrillation↗