Prevalence of and variables associated with silent myocardial ischemia on exercise thallium-201 stress testing

AbstractThe prevalence of silent myocardial ischemia was prospectively assessed in a group of 103 consecutive patients (mean age 59 ± 10 years, 79% male) undergoing symptom-limited exercise thallium-201 scintigraphy. Variables that best correlated with the occurance of patients ischemia by quantitative scintigraphic criteria were examined. Fifty-nine patients (57%) had no angina on exercise testing. A significantly greater persent of patients with silent ischemia than of patients with angina had a recent myocardial infarction (31% versus 7%, P < 0.01), had no prior angina (91% versus 64%, p < 0.01), had dyspnea as an exercise test end point (56% versus 35%, p < 0.05) and exhibited redistribution defects in the supply regions of the right and circumflex coronary arteries (50% versus 35%, p < 0.05). The group with exercise angina had more ST depression (64% versus 41%, p < 0.05) and more patients with four or more redistribution defects.However, there was no difference between the two groups with respect to mean total thallium-201 perfusion score, number of redistribution defects per patient, multivessel thallium redistribution pattern or extent of angiographic coronary artery disease. There was also no difference between the silent ischemia and angina groups with respect to antianginal drug, usage, prevalence of diabetes mellitus, exercise duration, peak exercise heart rate, peak work load, peak double (rate-pressure) product and percent of patients achieving ≥85% of maximal predicted heart rate for age.Thus, in this study group, there was a rather high prevalence rate of silent ischemia (57%) by exercise thallium-201 criteria. Patients with silent ischemia and those with exercise angina had comparable 1) exercise tolerance and hemodynamics, 2) extent of angiographic coronary artery disease, and 3) extent of exercise-induced hypoperfusion. Finally, more patients with recent infarction had silent ischemia than had exercise angina

The interaction of learning styles with learner control treatments in an interactive videodisc lesson on astronomy

The purpose of this study was to examine the interaction of different learning styles with different instructional presentations involving learner control while using an interactive videodisc system. Specifically, the issue was to determine if field-independent and field-dependent learners would perform differently from each other under different instructional treatments where the amount of learner control was varied through the environment of interactive videodisc learning. Learning styles were measured by the Concealed Figures Test, which identified the learner as being either field dependent or field independent. The eighty-seven college students participating in the study were randomly assigned to one of three treatment groups, Program Control, Student Control, or Experimental Control. The Program Control treatment provided the learner limited choices in the pace, path, and amount of instructional exposure. The Student Control treatment provided the learner maximum choices as to pace, path, and amount of instructional exposure. The Experimental Control treatment was a non- interactive videodisc program, consisting of a self-study guide

Vertebral rotation measurement: a summary and comparison of common radiographic and CT methods

Current research has provided a more comprehensive understanding of Adolescent Idiopathic Scoliosis (AIS) as a three-dimensional spinal deformity, encompassing both lateral and rotational components. Apart from quantifying curve severity using the Cobb angle, vertebral rotation has become increasingly prominent in the study of scoliosis. It demonstrates significance in both preoperative and postoperative assessment, providing better appreciation of the impact of bracing or surgical interventions. In the past, the need for computer resources, digitizers and custom software limited studies of rotation to research performed after a patient left the scoliosis clinic. With advanced technology, however, rotation measurements are now more feasible. While numerous vertebral rotation measurement methods have been developed and tested, thorough comparisons of these are still relatively unexplored. This review discusses the advantages and disadvantages of six common measurement techniques based on technology most pertinent in clinical settings: radiography (Cobb, Nash-Moe, Perdriolle and Stokes' method) and computer tomography (CT) imaging (Aaro-Dahlborn and Ho's method). Better insight into the clinical suitability of rotation measurement methods currently available is presented, along with a discussion of critical concerns that should be addressed in future studies and development of new methods

The Interaction of Learning Styles With Learner Control Treatments in an Interactive Videodisc Lesson on Astronomy

The purpose of this study was to examine the interaction of different learning styles with different instructional presentations involving learner control while using an interactive videodisc system. Specifically, the issue was to determine if field-independent and field-dependent learners would perform differently from each other under different instructional treatments where the amount of learner control was varied through the environment of interactive videodisc learning. Learning styles were measured by the Concealed Figures Test, which identified the learner as being either field dependent or field independent. The eighty-seven college students participating in the study were randomly assigned to one of three treatment groups, Program Control, Student Control, or Experimental Control. The Program Control treatment provided the learner limited choices in the pace, path, and amount of instructional exposure. The Student Control treatment provided the learner maximum choices as to pace, path, and amount of instructional exposure. The Experimental Control treatment was a non- interactive videodisc program, consisting of a self-study guide. Data from the pre-tests, post-tests, and recall tests were analyzed using descriptive methods for means and standard deviations and Analysis of Variances (ANOVAs) were used for measuring the main effects of the treatments and the interaction effects between learning styles and the treatments of learner control. The results of the study indicated improvement in learning achievement when using the interactive videodisc tutorial as compared with learning from a printed text containing similar subject content. There was no significant difference of post-test performance between those students assigned to the Student Control group and the Learner Control group, however, there was a significant difference between the two groups when compared with the Experimental Control group. There were differences of performance between the field dependents and field independents assigned to the three treatment groups. However, the differences were not significant. Finally, there was a significant interaction of learning styles, with the treatment groups for learning control, indicating that for the field dependent student, the Student Control method was the better, while for the field indepen­dent student, the Program Control method was the best. However, the interactions are the reverse of what was predicted for each learning style. A post-hoc analysis of time-on-task data is used to explain this situation

Myocardial contrast echocardiography in humans. II. Assessment of coronary blood flow reserve

AbstractThe hypothesis that myocardial contrast echocardiography could be used to simultaneously assess coronary blood flow reserve and the size of the perfusion bed supplied by a coronary artery was examined in nine patients and six dogs. All patients were undergoing cardiac catheterization and had single vessel coronary artery disease (≥85% stenosis of either the proximal left anterior descending or the left circumflex coronary artery); the six dogs had a critical stenosis of the left circumflex coronary artery. Three milliliters of sonicated Renografin-76 (mean microbubble size 6 μm) was injected into the left main coronary artery before and after intracoronary administration of papavarine, 6 to 9 mg. The beds supplied by the normal and stenotic vessels could not be differentiated during contrast echocardiography before injection of papavarine. However, after papavarine, the normal vascular bed showed significantly more contrast enhancement than did the bed supplied by the stenotic artery. This disparity in contrast enhancement made it possible to delineate the size of the bed perfused by the stenotic vessels.When quantitative analysis of the time-intensity curves obtained from the echocardiograms was performed in the dogs, the absolute values for the area under the curve, peak contrast intensity and curve width did not correlate with absolute blood flows measured with radiolabeled microspheres. However, the ratios of the areas under the curves derived from the two vascular beds before and after papavarine correlated well with the ratios of blood flows between the two beds during the same stages (r2= 0.73 by linear regression and r2= 0.85 by an exponential function). In comparison, the ratios of peak amplitudes and curve widths before and after papavarine had poor correlations with ratios of flows from the two beds (r2= 0.18 and 0.02, respectively).In conclusion, myochardial contrast echocardiograpgy can be used to simultaneously assess coronary blood flow reserve and the size of the perfusion bed supplied by a stenotic vessel

Younger women\u27s perceptions of coping with breast cancer

Numerous studies have demonstrated an association between coping strategies and better quality of life after breast cancer. Because younger women consistently show greater psychological morbidity than older women after breast cancer diagnosis, there is great interest in the coping strategies of younger women. The present cross-sectional study used quantitative and qualitative methods to examine coping strategies used by 201 women who were aged 50 years or younger at diagnosis and were 6 months to 3.5 years postdiagnosis. Quantitative results from a modified version of the Ways of Coping scale revealed that the most frequently used coping strategies were positive cognitive restructuring, wishful thinking, and making changes. Qualitative analyses based on open-ended questioning of how women best coped with different stressful aspects of their diagnosis showed that women reported finding different strategies useful depending on the stressor. For example, social support was helpful in dealing with anger or depression, whereas positive cognitive restructuring was more helpful for concerns about the future. Analyses also confirmed that most coping strategies cited in commonly administered coping scales were used frequently by these women. However, several coping strategies not generally measured were also deemed valuable, including engaging in physical activity, using medications, and resting. These findings suggest that clinicians should identify patients\u27 particular stressors and help with coping techniques targeting particular concerns