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Biomedical subjects

R A Bruce

Publications and source records attributed to R A Bruce.

At least 91 records · Page 5Linked to original sources
PubMed1982

Evaluation of automated blood pressure measurements during exercise testing.

Measurements of systolic (SBP) and diastolic (DBP) blood pressure were made at rest and during symptom-limited exercise with an automated blood pressure measuring device (EBPM). Comparisons were made between the EBPM readings and those made with mercury manometer. Correlations were high (SBP r = 0.92, DBP r = 0.80) when readings were made in the same arm, but were less satisfactory when the cuffs were on different arms (SBP r = 0.80, DBP r = 0.46). The correlation between two mercury manometer readings was SBP r = 0.90, and DBP r = 0.75. Comparison between EBPM and intra-arterial measurements were similar (SBP r = 0.74, DBP r = 0.79) to comparison between mercury manometer and intra-arterial measurements (SBP r = 0.81, DBP r = 0.61). The EBPM detected SBP at consistently higher levels than did physicians, which may be an advantage in the noisy environment of an exercise test. There was a definite tendency for physicians to record blood pressure to the nearest 10 mm Hg, whereas the frequency distribution curve for EBPM measurements was smoother. The EBPM operated satisfactorily at rest and during maximal exercise and gave as reliable measurements as a physician using a mercury manometer and, in the small number of available cases, detected exertional hypotension more often than the physician.

Blood Pressure↗
PubMed1982

Chemotherapy for treatment of choroidal metastases from breast carcinoma.

Of 15 patients with choroidal metastases from breast carcinoma, eight were treated with radiation therapy and six with chemotherapy. One patient received both. Although five of the six patients receiving chemotherapy died after an average follow-up period of 12 months, these patients generally had more widespread disease and a worse prognosis originally. Chemotherapy proved to be as effective as radiation therapy for this tumor.

Adult↗
PubMed1982

Sensitivity for Telemed diagnosis of myocardial infarction by use of 12-lead electrocardiogram derived from Frank XYZ leads.

Another comparison of sensitivity for diagnosis of myocardial infarction in conventional and derived 12-lead ECGs processed by the computer diagnostic program of the Telemed Cardio-Pulmonary System is reasonably consistent with the original trial of these two methods of recording ECG signals reported earlier by Dower and Machado. Other similarities and disparities are cited, together with brief comments about the theoretical and clinical implications of those findings and the relationship to a more rigorous analysis from this laboratory.

Computers↗
PubMed1982

Comprehensive evaluation of electrocardiographic methods for detection of myocardial infarction.

In two groups of patients the detection of myocardial infarction (MI) by analysis of four different electrocardiographic methods was evaluated. The various methods included the conventional 12 lead ECG (CV-ECG), the 12 lead ECG derived from Frank XYZ lead system signals (D-ECG), the polarcardiogram (PCG) and the vectorcardiogram (VCG). An invasive group consisted of 137 patients who had undergone cardiac catheterization. An MI was defined as a regional wall motion abnormality in the distribution of a coronary artery with at least 70% diameter reduction. The noninvasive group consisted of 116 patients in whom independent clinical information was limited to noninvasive assessments. In this group, Telemed Computer Systems' interpretation of the conventional (TC-ECG) and derived (TD-ECG) electrocardiogram was also available for comparison. An MI was defined in this group as either a compatible history with documented cardiac enzyme elevations, a resting defect on thallium scan, or a regional wall motion abnormality in a resting, radionuclide isotope ventriculogram. In this study the other methods of ECG evaluation demonstrated no advantage over the electrocardiographer's reading of the conventional ECG.

Adult↗
PubMed1982

Acute and chronic effects of diltiazem on A-V conduction at rest and during exercise.

The acute and chronic electrocardiographic effects of diltiazem, a drug which inhibits calcium passage through slow channels, were examined both at rest and during symptom-limited exercise. In the acute study, 12 patients with coronary artery disease (CAD), three patients with hypertrophic cardiomyopathy (HCM), and one patient with both CAD and HCM performed symptom-limited upright exercise prior to and one hour after receiving 120 mg oral dose of diltiazem. In the chronic study, three dose levels of diltiazem (120 mg/day, 180 mg/day, 240 mg/day) were compared with placebo in ten patients with CAD. Each patient received one week of placebo followed by placebo or diltiazem in a double-blind random cross-over fashion, so that each patient received four weeks of placebo and three weeks of diltiazem, one week at each dose level. Each week, symptom-limited upright exercise testing was performed. In the acute study, diltiazem did not significantly affect the mean PR, QRS, QTC intervals or the heart rate at rest or at maximal exercise. In one patient, diltiazem markedly slowed the ventricular response to atrial fibrillation and in another patient, provoked transient Mobitz I block. In the chronic study, the only significant difference observed was a prolongation of the resting PR interval on the 240 mg/day dose schedule (p less than .005).

Administration, Oral↗
PubMed1982

Estimation of myocardial infarct size by digital computer analysis of the VCG.

This study described the linear relationship of the myocardial infarct size, measured postmortem, to the integral of the sequential vector spatial magnitudes analyzed at 400 samples per second during the initial period of abnormal depolarization (IAD) in 25 patients with myocardial infarction (MI) and ten controls. The equation for the fitted regression line was: %MI = -0.35 + 3.33 IAD; r = .90; p less than .001. The duration of abnormal depolarization was determined by two computer algorithms: first, using the classical method of pathological Q wave duration, whenever possible; and a new method of measurement of an abnormally slow rate of rise of vector spatial magnitude with time (dm/dt), when there were no Q waves in the Frank orthogonal lead input signals. There was not a significant difference in the mean values of IAD of the MI group or the control group calculated by the two algorithms.

Aged↗
PubMed1982

Maximal cardiac function in sedentary normal men and women: comparison of age-related changes.

The normal range of maximal values for oxygen consumption, heart rate, cardiac index, and stroke index during treadmill exercise testing are presented for 98 men and 104 women for ages 20-75 yr. These variables decrease with age in both sexes, but men show a significantly greater reduction than women with respect to oxygen consumption (P = 0.05), heart rate (P less than 0.02), and cardiac index (P less than 0.02). Comparison of the normal ranges of oxygen consumption, cardiac index, and stroke index indicated that men have significantly higher values than women (P less than 0.001). The normal range of heart rate was higher in younger men than women, but because of a more rapid decline with age in men, the older women had higher heart rates than the older men. Invasive measurements of cardiac index in 12 normal men and 11 normal women were within the defined normal range. These measurements showed that there was a greater increase in stroke index from supine rest to maximal upright exercise in men compared with the increase in women (means +/- SD, 12 +/- 9 m/m2 vs. 2 +/- 7 ml/m2, P less than 0.01).

Adult↗
PubMed1982

Treadmill test responses to an early exercise program after myocardial infarction: a randomized study.

The effects of an exercise program started early after myocardial infraction and the added effects of an outpatient teaching-counseling program were studied. At random, 84 patients were allocated to a control group (A), 88 patients to an exercise group (B1) and 86 patients to an exercise and teaching-counseling group (B2). The same exercise program was prescribed for patients in groups B1 and B2 and was started about 4.5 days after myocardial infarction and continued for 3 months. The outpatient teaching-counseling program consisted of eight group sessions pertaining to risk factor reduction and psychosocial adjustment to myocardial infraction. A low-level treadmill test and an exercise test were performed at 3 months and the exercise test was repeated at 6 months. The clinical, hemodynamic and electrocardiographic responses to these tests were not different among the three groups. However, by the end of 3 months, patients in group B1 and B2 reported walking greater distances than patients in group A. The incidence of morbidity and mortality was not different between the groups. No deleterious or beneficial physiologic effects of an exercise program either by itself or combined with a teaching-counseling program were demonstrated. Routine medical care and our interventions were equally effective in permitting the spontaneous hemodynamics improvements after myocardial infraction. More than 3 months after myocardial infarction, the group as a whole manifested spontaneous recovery in the form of a significant decrease in resting heart rate (p less than 0.001) and a significant increase in systolic and diastolic blood pressure at rest and with submaximal exercise (p less than 0.001). No further improvements were observed between 3 and 6 months.

Blood Pressure↗
PubMed1982

Metastatic carcinoid to the choroid.

This article describes the seventh published case of metastatic carcinoid to the choroid. Only two prior cases have been treated conservatively, one using chemotherapy and the other using photocoagulation and proton beam irradiation. Our patient was unique since she was the first to have conservative therapy by implantation of a radon ring. Initial results were clinically promising, although repeated ultrasound testing actually showed minimal decrease in tumor size. Subsequently, a large retinal detachment caused marked visual deterioration. Persistent pain from neovascular glaucoma prompted later enucleation, and silver staining as well as electron microscopic studies were performed on the choroidal lesion. It was found that the radon ring had little histologic effect on the viability of the tumor cells. This contrasted with an earlier report of the successful treatment of two much smaller choroidal lesions, using external proton beam irradiation. From our pathologic evaluation, we believe that the metastatic carcinoid tumor should be considered relatively radioresistant.

Adult↗
PubMed1981

In-hospital exercise after myocardial infarction does not improve treadmill performance.

Prolonged bed rest after myocardial infarction is thought to result in deconditioning, manifested by increased heart-rate and blood-pressure responses to exercise and decreased functional capacity. We studied the effects of early, supervised exercises in preventing deconditioning after acute myocardial infarction. Eighty-four patients were randomized to a control group and 174 to an exercise group. Enrollment in the exercise program occurred an average of 4.5 days after admission (range, one to nine). Discharge from the hospital occurred an average of 10.3 days after admission in the control group and 10.4 days in the exercise group. Most patients had a low-level treadmill test on the day before hospital discharge. There were no differences between the two groups in the clinical, hemodynamic, or electrocardiographic responses to the treadmill test. Incidences of complications and deaths (one death in each group) during hospitalization were not significantly different in the two groups, although six patients (3 per cent, all in the exercise group) required cardiac surgery--four because of recurrent chest pain and two because of rupture of heart muscle. Thus, we were unable to demonstrate any significant beneficial or deleterious effects of an early, in-hospital exercise program.

Aged↗
PubMed1981

Altered exercise ventilatory responses by apparent propranolol-diminished glucose metabolism: implications concerning impaired physical training benefit in coronary patients.

The effect of a single oral 40 mg dose of propranolol on ventilatory responses to symptom-limited maximal exercise were studied in 14 coronary artery disease (CAD) patients and in four normal volunteers. In both groups, there was significant reduction of carbon dioxide production, minute ventilation, and respiratory exchange ratio at matched workloads. Propranolol did not affect oxygen uptake at matched workloads. A possible explanation of these findings was that propranolol, as a result of beta blockade, inhibited stimulation of glucose metabolism during exercise. Such an effect may diminish ability of CAD patients taking propranolol to obtain beneficial results of an exercise training program.

Adult↗