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Biomedical subjects

S T Anderson

Publications and source records attributed to S T Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1980

The radionuclide assessment of left ventricular function using graded exercise in normal subjects.

In 20 normal volunteers, two minute equilibrium gated blood pool scanning (GBPS) was used to assess left ventricular function during rest and three stages of graded supine exercise on a bicycle ergometer. The three work loads were individualised for each subject from a previously performed exercise test and corresponded to mild, moderate and severe stress. The short imaging time was validated against standard GBPS. With exercise all subjects increased their left ventricular ejection fraction and in the majority, most of this rise occurred with the lowest work load. This change was predominantly due to a marked fall in end-systolic volume. The end-diastolic volume initially fell, then at peak exercise returned to baseline values. The major change in stroke volume occurred at peak exercise.

Adult↗
PubMed1979

Myocardial infarct imaging after cardiac surgery.

One hundred and nineteen patients undergoing cardiac surgery had postoperative myocardial imaging performed with technetium pyrophosphate in order to assess the incidence of perioperative myocardial infarction. Fifty-six patients had only coronary artery bypass graft (CABG) surgery, of whom 13(23%) had a positive scintigram. Thirteen patients had CABG with other cardiac surgery and six (46%) had a positive scintigram. Fifty patients had other cardiac surgery but no CABG, and of these eight (16%) had a positive scintigram. The overall incidence of positive scintigrams was 23%, whereas definite or probable ECG diagnosis of infarction was present in 14 patients (12%). Serum levels of cardiac enzymes were higher in patients with positive scintigrams, but this finding did not consistently reach statistical significance. The use of a left ventricular vent during surgery did not correlate with a positive scintigram, nor did the total time on cardiopulmonary bypass or aortic cross-clamping. Patients having cardiac surgery, including CABG and valve replacement, have a 23% overall incidence of positive scintigrams. This suggests that the incidence of infarction after cardiac surgery is higher than can be recognized from the conventional criteria of ECG and enzyme changes.

Cardiac Surgical Procedures↗
PubMed1978

A comparison of the Jones and Stead-Wells spirometers.

A comparison was made between the noncounterweighted Jones and Stead-Wells spirometers, and "conversion factors" were determined for the forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC). A cross-sectional study produced a high correlation between the instruments for these two measurements, yielding quadratic and linear regression equations ("conversion factors") for FEV1 and FVC, respectively. Standard deviations of measurements were similar for both spirometers. Results from a longitudinal study agreed with the "conversion factors" predicted from the cross-sectional study; however, significant day-to-day variability was observed by both spirometers. Neither spirometer met all of the technical recommendations proposed by the Committees on Environmental Health and Respiratory Physiology of the American College of Chest Physicians; however, the Stead-Wells water-sealed spirometer complied more often than the Jones waterless spirometer (Pulmonor). In addition, the open-circuit procedure used for the Jones spirometer required more corrdination in the subject than did the closed-circuit procedure employed in this study for the Stead-Wells spirometer; however, with application of the "conversion factors," both instruments, yield comparable data and prove adequate for spirometric studies.

Forced Expiratory Flow Rates↗
PubMed1977

Imaging of acute myocardial infarction using technetium 99m labelled phosphate compounds.

Technetium 99m pyrophosphate or polyphosphate administered intravenously soon after acute myocardial infarction produces positive images of the area and extent of myocardial necrosis. Forty-four patients have been studied of whom 39 had myocardial infarction. There was good correlation of the site and extent of infarction as indicated by the scintigram with electrocardiogram and cardiac enzyme criteria.

Acute Disease↗
PubMed1977

Pulmonary embolism secondary to anomalies of deep venous system of the leg.

Two cases of recurrent pulmonary emboli secondary to thrombosis in anomalies of the deep veins of the lower limb are presented. In both cases the source of emboli was not evident clinically, and it was only after venography that the venous anomalies were discovered, both being confined to one limb and amenable to surgical intervention. Such anomalies have not previously been reported as sources of venous thromboembolism in adults. The importance of venography in establishing the source of pulmonary emboli, especially when recurrent, is stressed.

Adult↗
PubMed1976

Interference with function of unipolar pacemaker due to muscle potentials.

One hundred and seventy-three unipolar pulse generator systems were tested in 169 patients to determine the incidence of sensing of muscle potentials. One hundred and twenty-two implants in the pectoral region were suitable for assessment and 60 (49 per cent) demonstrated sensing. Ventricular-inhibited units sensed muscle potentials in 69 per cent (47 of 78), with 9 patients complaining of related symptoms. Ventricular-synchronous units sensed in 30 per cent (13 of 34) with no patient manifesting symptoms.

Action Potentials↗
PubMed1970

Haemodynamic factors influencing opening snap interval in mitral stenosis.

Various haemodynamic measurements were correlated with the A2-OS interval in 35 patients with pure or predominant mitral stenosis. There was good correlation of left atrial V wave pressure, left ventricular systolic pressure, and mitral mean diastolic gradient with A2-OS. There was no significant correlation of mitral valve area with A2-OS. When the left ventricular pressure was arbitrarily assigned to one particular pressure (100 mm. Hg) correlations with all other variables improved. There was still no correlation of A2-OS interval with mitral valve area. These and other haemodynamic factors influencing the A2-OS interval are briefly discussed.

Blood Pressure↗