Task Force II: Determination of occupational working capacity in patients with ischemic heart disease.
Explore the source record for details and available documents.
Coronary Disease↗
Biomedical subjects
R A Bruce
Publications and source records attributed to R A Bruce.
Improvements in exercise electrocardiography.
Explore the source record for details and available documents.
Coronary Disease↗
Strategies for risk evaluation of sudden cardiac incapacitation in men in occupations affecting public safety.
Sudden cardiac incapacitation occurring during critically stressful circumstances in men engaged in a variety of occupations may compromise public safety. Since the primary cause of this incapacitation is usually heart disease, more effective medical screening has been advocated. We report the annual incidence of sudden cardiac incapacitation in four clinical groups--4105 healthy men (Group I), 537 men with atypical chest pain syndromes (Group II), 1374 hypertensive men (Group III), and 2373 men with clinically manifest coronary heart disease (Group IV)--who have been examined and tested by maximal exercise with the Bruce protocol in Seattle community practice. Five strategies for prospective risk assessment are presented in these groups, namely age alone, clinical diagnosis before testing, the combination of both parameters, exercise-enhanced risk assessment, and the exercise criteria proposed by a Task Force for Ischemic Heart Disease (Bethesda Conference XVIII, 1986). We conclude that the exercise-enhanced risk assessment is the most effective of these strategies.
Accident Prevention↗
The effect of antenatal surgery on postnatal palatal growth in sheep.
It has been suggested that repair of skin and mucosal wounds carried out in animals in utero leaves little or no trace of the operative procedure when examined at birth. This study examined the palates of lambs affected surgically in utero postnatally for scarring and transverse palatal growth. Nineteen pregnant sheep were affected at 120 days gestation. Surviving lambs followed for 6 months demonstrated altered palatal morphology.
Animals↗
ST segment elevation with exercise: a marker for poor ventricular function and poor prognosis. Coronary Artery Surgery Study (CASS) confirmation of Seattle Heart Watch results.
The functional and prognostic significance of exercise-induced ST elevation (by computer averaging) in ambulatory patients with coronary heart disease was recently reported for 181 patients in the Seattle Heart Watch (SHW). To further evaluate this, 3050 approximately similar patients enrolled in CASS were analyzed with respect to initial findings, survival, and incidence of secondary coronary events over the next 6 years. The ST elevation responses in CASS patients were classified by visual interpretation of 1 mm or more, whereas the SHW patients were identified by voltage greater than 0 mV. Accordingly, prevalence of exercise-induced ST elevation was lower in CASS patients, but they had greater frequencies of prior myocardial infarction and left ventricular enlargement and dysfunction. The poor survival was similar in the subgroup with ST elevation during exercise and recovery in CASS and SHW. Although not an independent predictor when invasive variables are known, ST elevation emerges as a useful predictor when exercise testing is performed before diagnostic invasive studies.
Coronary Disease↗
Oral and maxillofacial surgery in China.
The primary author is a 41-year-old oral and maxillofacial surgeon on the attending staff of the Stomatology Hospital of Nanjing Medical University in Nanjing, China. He is currently a visiting scholar at the University of Michigan and has a wide variety of experience in medicine and dentistry, including 11 years of general surgery, plastic surgery, and tumor surgery training in addition to his stomatology education. His experiences during the past 20 years have prompted his American colleagues to encourage him to present his views with respect to oral and maxillofacial surgery in China today. The purpose of this article is to promote understanding among colleagues in China and in the West.
China↗
Differentiation of the organic matrix in bone repair.
This study describes the sequence of production and distribution of collagen, collagen types, proteoglycans, and calcium during bone repair in rabbits utilizing histologic and biochemical techniques. Proteoglycan content peaked 11 days following surgery and total collagen peaked 19 days after surgery, after which both levels decreased. Collagen Types I and III were present in the bone defect throughout the healing process but Type II was found only in the mid stages of repair. In the surrounding external callus Types I, II, and III were present, but Type III was not noted in the later stages of healing. These results are similar to those found in studies of fracture repair and developing bone.
Animals↗
Exercise-enhanced assessment of risk factors for coronary heart disease in healthy men.
Exercise-enhanced risk assessment for subsequent morbidity and mortality due to coronary heart disease in 4105 asymptomatic healthy men (mean age of 44.6 +/- 7.9 years) is reported for in Seattle community practice. Annual incidence of primary coronary events ranges from 0.22% in 1792 men (43.6%) without conventional risk factors, to 0.42% in the majority of men (55.3%) with any risk factor(s) and less than two abnormal responses to maximal exercise. Among 44 men (1.1%) at high risk defined by any conventional risk factor(s) and any two or more abnormal responses to maximal exercise, annual incidence of primary coronary events is 5.2% (P less than 0.001). Of 1718 men under 60 years of age without conventional risk factors, 117 or 6.8% who developed ischemic ST depression with maximal exercise testing are false positive responders since no coronary event occurred during the next five years.
Adult↗
Health benefits of exercise in an aging society.
The effects of regular aerobic exercise are important to an aging society increasingly preoccupied with exercise. Traditionally, most attention has been directed to the relationship between a physically active life-style and cardiovascular mortality. In an aging society, however, active life expectancy and maintenance of independence may be as important as effects of regular exercise on longevity. Regular exercise results in increased maximum aerobic capacity due to peripheral changes in muscle (increased capacity for aerobic metabolism and improved substrate and oxygen extraction with a widened arteriovenous oxygen difference) and also due to cardiovascular changes with increased stroke volume and cardiac output in normal persons. "Therapeutic benefits" of conditioning probably occur at submaximal work loads common to everyday activity, when cardiac work and myocardial oxygen consumption are less for any given work load, muscles are more efficient, and relative oxygen requirements are less. Aging is associated with a linear decline in maximum aerobic capacity. The rate of decline is twofold greater when comparing sedentary with physically active middle-aged men. Thus, regular exercise could conceivably lower functional aerobic age by slowing this functional decline. Exercise, particularly excessive exercise, is also associated with serious hazards, including sudden death, nonfatal myocardial infarction, excessive fatigue, hyperthermia, and significant musculoskeletal problems. Accounts of the health effects of exercise should consider a wide range of risks and benefits, especially those related to improving function, minimizing disability, and prolonging independent living.
Aging↗
Exercise-enhanced risk factors for coronary heart disease vs. age as criteria for mandatory retirement of healthy pilots.
Exercise-enhanced risk assessment for subsequent morbidity and mortality due to coronary heart disease is examined in 4105 asymptomatic healthy men of 15 to 80 years of age (mean of 44.7 years) observed in Seattle community practice. Annual incidence of primary coronary events averages 0.22% in 1792 men (43.6%) without conventional risk factors, and 0.42% in the majority of men (55.3%) with risk factor(s), but less than two abnormal responses to maximal exercise. Among 44 men (1.1%) at high risk defined by any conventional risk factor(s) and two or more abnormal responses to maximal exercise, annual incidence of primary coronary events averages 5.2% (p less than 0.001). The proportion of men of 60-64 years at low risk with a 98% 3-year survival rate is 16 times that of men of 55-59 years at high risk with a 78% survival rate in this asymptomatic population. Of 1718 men under 60 years of age and without conventional risk factors, 117 or 6.8% developed ischemic ST depression with maximal exercise testing, but none reported any coronary event during 5.6 years of follow-up surveillance.
Aerospace Medicine↗
Unusual prognostic significance of exercise-induced ST elevation in coronary patients.
Follow-up surveillance of 1136 coronary patients (918 men and 218 women) observed in Seattle community practice reveals a higher incidence of subsequent myocardial infarction, cardiac arrest or cardiac death in over 4% who manifested ST elevation during maximal exercise testing and recovery. Quantitative measurements of 100-beat signal-averaged ECG responses transmitted by dataphone from 15 testing sites provide objective classification into ST depression (less than O mV) and ST elevation (greater than O mV) during exercise and five minutes of recovery. Whereas the annual incidence of CHD events in 18.3% of men with ST depression only during exercise is 2.0%/year, it is 4.1%/year in 71.6% of men with ST depression persisting into recovery and 8.2%/year with ST elevation during exercise and recovery (P less than 0.05). Even higher event rates occur with exercise of short duration and in a subgroup who had invasive studies which demonstrated at least two vessels with 70% or more stenosis and ejection fractions under 50%.
Coronary Disease↗
Validation of a computerized QRS criterion for estimating myocardial infarction size and correlation with quantitative morphologic measurements.
This replication study describes the relation of myocardial infarction (MI) size, measured at autopsy, to initial and late QRS abnormalities, measured by computerized spatial vectorcardiography. Thirty-one patients with MIs of differing ages and left ventricular locations and 24 patients with no evidence of heart disease were studied. The percent volume of MI was significantly estimated by the initial QRS abnormalities (r = 0.94, p less than 0.00001). The 2 regression equations from the previous training set and from this present test set were compared to verify validity of the criterion, the integral of magnitudes of spatial vectors during initial abnormal depolarization to estimate MI size. There was not a significant difference between the 2 intercepts, the 2 slopes, the 2 straight-line regressions or the 2 correlation coefficients. The additional information obtained from late QRS abnormalities contributed little to improve estimation of size of multiple MIs of differing ages and left ventricular locations, but accurately predicted (r = 0.87) the size in single inferobasal MI. The results indicate that vectorcardiographic measurements of early activation abnormalities is a valid criterion to estimate MI size.
Aged↗
Physical activity and coronary artery disease.
Explore the source record for details and available documents.
Coronary Disease↗
Excessive reduction in peripheral resistance during exercise and risk of orthostatic symptoms with sustained-release nitroglycerin and diltiazem treatment of angina.
Acute effects of placebo, sustained-release nitroglycerin, diltiazem capsules, and the combination of both drugs were monitored in nine stable angina patients. They were randomized to receive either placebo or 13 mg of slow-release nitroglycerin orally (double-blind). This was followed in 1 hour by 120 mg of diltiazem orally, given to all patients (unblinded). Invasive hemodynamic measurements were made before and after each treatment at supine and sitting rest, two levels of submaximal, and at maximal exercise and twice in recovery. Compared to the control test at maximal exercise, sustained-release nitroglycerin increased aerobic capacity 24%, lowered peripheral resistance -32%, and lowered systemic pressure -23%, while the respective changes with placebo were -3%, 5%, and 2%. When diltiazem was added to placebo compared to the control test, there was a 4% increase in oxygen consumption and -9% and -4% reduction in systemic resistance and systemic pressure, respectively. The addition of diltiazem to nitroglycerin was associated with a 20% increase in oxygen consumption a -42% reduction in systemic resistance and a -32% reduction in systemic pressure. Two patients who received nitroglycerin plus diltiazem experienced symptomatic hypotension, while one patient who received placebo plus diltiazem experienced hypotension. These side effects caused the study to be terminated prematurely. Thus, although the combination of nitroglycerin and diltiazem had a greater effect on afterload than either drug alone, the combination did not provide greater improvement in cardiac performance.
Aged↗
Relationships of working status and cardiac capacity to functional age before and after coronary bypass surgery.
In 77 patients having coronary bypass surgery, we evaluated the interaction between chronological age, functional age, and working status pre- and postoperatively. Preoperatively the chronological age of those not working compared to those working was 60.7 +/- 8.4 years versus 53.0 +/- 8.3 years (P less than 0.001). The preoperative functional ages were 93.5 +/- 11.5 versus 87.6 +/- 10.9 years (P less than 0.05). Postoperatively no patient who was not working preoperatively started work, although functional age improved from 93.5 +/- 11.5 to 83.2 +/- 12.8 years (P less than 0.001). Postoperatively subjects who stopped working showed similar improvement in maximal cardiac output, and maximal oxygen consumption compared to those who continued working; however, the functional age after surgery was 80.6 +/- 9.4 versus 69.6 +/- 11.6 years (P less than 0.01). This study showed a poor relationship between degree of improvement in cardiac function after bypass surgery and change in working status. However, functional age and chronological age contribute to the poor results with regard to return to work.
Age Factors↗
Comparative accuracy of computerized spatial vectorcardiography and standard electrocardiography for detection of myocardial infarction.
New computerized spatial vectorcardiographic variables were analyzed by discriminant analyses for group classification of 94 patients with acute myocardial infarction and 79 normal subjects. Using the integral of the sequential magnitudes of the spatial vectors during the period of initial abnormal depolarization (IAD) of the QRS at a discriminating value of 3 mv X msec., 87% of the subjects were correctly classified with a sensitivity of 85%; specificity of 88%; and an overall predictive accuracy of 87%, p less than .00001. The period of initial abnormal depolarization in which the vectors were integrated was determined by the first derivative of the sequential magnitudes of the spatial vectors of the QRS waveform (dm/dt). The mean value of dm/dt during the period of abnormal depolarization was a poor discriminating variable. The predictive accuracy of this new electrocardiographic criterion for diagnosis of myocardial infarction compared favorably with other computerized methods such as vectorcardiography, polarcardiography, Aitoff spatial trajectory, the 12-lead ECG derived by the Frank XYZ leads as well as the standard 12-lead ECG.
Computers↗
Validation of exercise-enhanced risk assessment of coronary heart disease events: longitudinal changes in incidence in Seattle community practice.
Noninvasive criteria developed in a learning series for exercise-enhanced risk assessment for events due to coronary heart disease have been applied to a test series in a later population sample. Men in the same age and risk groups for each pretest clinical classification show similar gradients of risk. Thus, exercise-enhanced criteria for risk assessment are validated. Age-standardized event rates show a reduction longitudinally in healthy men and patients who have had coronary bypass surgery.
Adult↗