Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Epidemiology and prevention of ventricular ectopic rhythms

Current work of the Laboratory of Physiological Hygiene is reviewed on the epidemiology and prevention of ectopic ventricular rhythms (VPB). The evidence suggests that uniform simple VPB at rest, or exercise-induced, are prognostically important only in those having clinically manifest coronary disease. A simple rhythm strip is an effective first screen method for detecting individuals having rather frequent VPB, and frequency of VPB is correlated with complex ectopic rhythms. A multifaceted stress induction test induces VPB and does it consistently. Hygienic intervention, in which cardiac stimulants are removed and conditioning exercises given, is being tested as VPB suppressive therapy.

Population strategies to enhance physical activity: the Minnesota Heart Health Program

A population-wide, community-based program in cardiovascular disease prevention, the Minnesota Heart Health Program (MHHP), has been designed to promote more frequent and vigorous physical activity in North American communities, along with improved eating and smoking patterns. The physical activity component of this broad-based education strategy is based on the facilitation which physical activity provides to lowering of other risk characteristics for heart disease and its enhancement of other healthy behaviors and on the potential for prevention of elevated risk in the first place. The rationale for a population strategy to complement medical approaches to prevention is that exercise patterns are largely socially learned and culturally determined. The MHHP Physical Activity Program is implemented through three major education strategies: direct education, community organization, and mass communications. Early results from this 10-year project indicate that it is feasible to enter U.S. communities and to involve their leadership actively in MHHP activities of health promotion. Moreover, attitudes, knowledge, awareness, participation, and behaviors related to exercise and eating patterns appear to be changed by the program. Nevertheless, there are problems in the design, implementation, analysis and interpretation of population changes in physical activity and other health behaviors in community demonstration programs. These issues, along with their solutions, should provide useful information for medical science and for the public health about population strategies of disease prevention and health promotion.

Independent risk for cardiovascular disease predicted by modified continuous score electrocardiographic criteria for 6-year incidence and regression of left ventricular hypertrophy among clinically disease free men: 16-year follow-up for the multiple risk factor intervention trial

Risk prediction for electrocardiographic (ECG) left ventricular hypertrophy related criteria, used in clinical trials, and epidemiologic studies of clinically healthy people, has depended in the past on dichotomous classification of ECG LVH criteria. Recent analyses have shown that more sensitive methods of LVH ECG classification without loss of specificity are needed to improve on dichotomous classification. This was done by relating six year incident significant change in continuous score criteria of ECG LVH to the 16 year (10 year post trial) coronary heart disease (CHD) and cardiovascular disease (CVD) mortality among 12,866 men, free of clinical disease, aged 35 to 57 years at baseline in the Multiple Risk Factor Intervention Trial. It was found that significant change in continuous ECG LVH criteria was a stronger independent predictor of future CHD and CVD mortality than was use of dichotomous classification of the same criteria. It was also demonstrated that increase in continuous ECG LVH indexes, below previous dichotomous thresholds independently (of standard CVD risk factors, including increase in obesity-indicated by an increase in adult BMI) predicted excess CHD and CVD mortality and that combinations of continuous indices increases the specificity and relative risk in clinically disease-free middle-aged men.

PREDICT: A simple risk score for clinical severity and long-term prognosis after hospitalization for acute myocardial infarction or unstable angina: the Minnesota heart survey

BACKGROUND

We evaluated short- and long-term mortality risks in 30- to 74-year-old patients hospitalized for acute myocardial infarction or unstable angina and developed a new score called PREDICT.

METHODS AND RESULTS

PREDICT was based on information routinely collected in hospital. Predictors abstracted from hospital record items pertaining to the admission day, including shock, heart failure, ECG findings, cardiovascular disease history, kidney function, and age. Comorbidity was assessed from discharge diagnoses, and mortality was determined from death certificates. For 1985 and 1990 hospitalizations, the 6-year death rate in 6134 patients with 0 to 1 score points was 4%, increasing stepwise to 89% for >/=16 points. Score validity was established by only slightly attenuated mortality prediction in 3570 admissions in 1970 and 1980. When case severity was controlled for, 6-year risk declined 32% between 1970 and 1990. When PREDICT was held constant, 24% of those treated with thrombolysis died in 6 years compared with 31% of those not treated.

CONCLUSIONS

The simple PREDICT risk score was a powerful prognosticator of 6-year mortality after hospitalization.

[Fatigue in the healthy and in cancer patients. II. A qualitative study for conceptual analysis]

A qualitative study to explore the concept of fatigue/tiredness in cancer patients and in healthy individuals Interest in fatigue-research has grown since the finding that fatigue/tiredness is the most frequently reported symptom of cancer and its treatment. But even though several authors have tried to conceptualise fatigue its mechanisms are still poorly understood. The aim of this study was twofold: 1. to explore fatigue in cancer patients, inductively, and 2. to compare experiences of fatigue/tiredness of healthy individuals with that of cancer patients to identify cancer-specific fatigue/tiredness and related concepts. A qualitative research strategy was adopted using a grounded theory approach. The prospective study took place in the Oncology Department of the Kantonsspital St. Gallen (Switzerland) with samples of 20 cancer patients and 20 healthy individuals. Unstructured, tape recorded interviews were conducted to collect data. The transcripts of the interviews were analysed using content analysis and constant comparison. Different themes emerged between the two groups although both fitted a classification system, which categorised fatigue into physical, affective and cognitive expressions of fatigue/tiredness. Physical signs were more frequent than affective and cognitive signs in both groups. In the cancer patients, fatigue involved decreased physical performance, extreme, unusual tiredness, weakness and unusual need for rest, which was distinctly different for healthy persons. Affective and cognitive distress was also more prominent in cancer patients. Interestingly, the concept of malaise was not identified by either sample and not understood as an expression of fatigue by this German speaking population. Linguistic differences in the description of fatigue/tiredness between healthy and ill individuals revealed different perceptions of the phenomenon. A step-like theory, explaining the production of fatigue/tiredness was tentatively put forward involving nociception, perception and expression of tiredness. The emerging concepts break tiredness/fatigue into expression of physical, affective and cognitive tiredness/fatigue. The experience is different between healthy individuals and cancer patients. Generalisability of data needs precaution but the results of the study identifies and clarifies ideas that might form an important basis for further, controlled studies.

[Fatigue in healthy and cancer patients. 1. A qualitative study on conceptual analysis]

Interest in fatigue-research has grown since the finding that fatigue/tiredness is the most frequently reported symptom of cancer and its treatment. But even though several authors have tried to conceptualise fatigue, its mechanisms are still poorly understood. The aim of this study was twofold: 1) to explore fatigue in cancer patients, inductively, and 2) to compare experiences of fatigue/tiredness of healthy individuals with that of cancer patients to identify cancer-specific fatigue/tiredness and related concepts.

PATIENTS AND METHODS

A qualitative research strategy was adopted using a grounded theory approach. The prospective study took place in the Oncology Department of the Kantonsspital St. Gallen (Switzerland) with samples of 20 cancer patients and 20 healthy individuals. Unstructured, tape recorded interviews were conducted to collect data. The transcripts of the interviews were analysed using content analysis and constant comparison.

RESULTS

Different themes emerged between the two groups although both fitted a classification system, which categorised fatigue into physical, affective and cognitive expressions of fatigue/tiredness. Physical signs were more frequent than affective and cognitive signs in both groups. In the cancer patients, fatigue involved decreased physical performance, extreme, unusual tiredness, weakness and unusual need for rest, which was distinctly different for healthy persons. Affective and cognitive distress was also more prominent in cancer patients. Interestingly, the concept of malaise was not identified by either sample and not understood as an expression of fatigue by this German speaking population. Linguistic differences in the description of fatigue/tiredness between healthy and ill individuals revealed different perceptions of the phenomenon. A step-like theory, explaining the production of fatigue/tiredness was tentatively put forward involving nociception, perception and expression of tiredness.

CONCLUSIONS

The emerging concepts break tiredness/fatigue into expression of physical, affective and cognitive tiredness/fatigue. The experience is different between healthy individuals and cancer patients. Generalisability of data needs precaution but the results of the study identifies and clarifies ideas that might form an important basis for further, controlled studies.

A standardized procedure for locating and documenting ECG chest electrode positions: consideration of the effect of breast tissue on ECG amplitudes in women

Continuing uncertainty exists about standardized procedures for the placement of electrocardiographic (ECG) chest electrodes, technical variability being the largest error source for short-term variations in amplitudes and waveforms of the chest lead ECGs. To avoid presumed attenuation of ECG amplitudes by abundant breast tissue, anterolateral chest electrodes in women are often placed under the breasts and too low. There is also considerable uncertainty about locating the midclavicular line and the V4 electrode, particularly in obese persons and in women. We examined the effect of breast tissue protuberance on ECG amplitudes using ECG and anthropometric data on 6,814 women included in the Atherosclerosis Research in Communities Study (ARIC). The R wave amplitudes in anterolateral chest leads and the Sokolow-Lyon voltage decreased (P < .001 for all), and RaVL and the Cornell voltage increased significantly with increasing breast protuberance (P < .001 for all). However, these effects were small (15 microV or less for each 1-cm increment in breast protuberance), and R2 values were less than .01, indicating that breast protuberance alone explained less than 1% of ECG amplitude variations. When chest size and breast protuberance estimates were entered simultaneously into a multivariate regression model, chest size appeared to dominate, and model R2 values increased for positive associations with RaVL (R2 = .12) and the Cornell voltage (R2 = .04). Combined model R2 values remained < or =.01 for all other ECG amplitudes. A detailed step-by-step standardized electrode placement procedure was formulated. Because of the difficulties encountered in locating the left midclavicular line by visual inspection, we introduced well-defined procedures for identification and documentation of lateral chest electrode placement locations as a quality control method for clinical trials. Population data from the Third National Health and Nutrition Survey on the distributions by sex and race of chest electrode V4 and V6 locations and anthropometric data on chest size and shape are presented in order to facilitate evaluation of the comparability of electrode placement procedures in various studies and for quality control in clinical trials. It is concluded that standardized procedures to document chest electrode placement locations are feasible. Breast tissue appears to have a practically negligible effect on ECG amplitudes, and in women, the placement of chest electrodes on the breast rather than under the breast is recommended in order to facilitate the precision of electrode placement at the correct horizontal level and at the correct lateral positions.

Cognitive processes nurses and doctors use in the administration of PRN (at need) analgesic drugs

The report is a descriptive, comparative study of the cognitive processes used by doctors and nurses when deciding whether or not to administer prn drugs to postoperative cancer patients. Simulations, together with the think aloud technique to provide verbal protocols was the method chosen. The theoretical framework chosen for the analysis was the information processing theory. Five doctors and 5 nurses, each with at least 5 years of working experience were interviewed. The interviews were transcribed so that a content analysis could be performed. The main findings were the following: doctors and nurses generated hypotheses early in the interview; the only statistically significant difference between the two groups was the wider use of theory and/or experience as a source of information by doctors. Although differences are not statistically significant, nurses appear to collect more information on and from the patient and more information on vital signs and symptoms other than pain than the doctors. Differences derived from analysis of the statements expressed by the subjects suggested that nurses pay more attention to the patient's psychological problems and that, while doctors' main concern was to make the right diagnosis, the nurses' main concern were patients' reactions and collaboration.

Community education for cardiovascular disease prevention. Morbidity and mortality results from the Minnesota Heart Health Program

The Minnesota Heart Health Program was a community trial of cardiovascular disease prevention methods that was conducted from 1980 to 1990 in three Upper Midwestern communities with three matched comparison communities. A 5- to 6-year intervention program used community-wide and individual health education in an attempt to decrease population risk. A major hypothesis was that the incidence of validated fatal and nonfatal coronary heart disease and stroke in 30- to 74-year-old men and women would decline differentially in the education communities after the health promotion program was introduced. This hypothesis was investigated using mixed-model regression. The intervention effect was modeled as a series of annual departures from a linear secular trend after a 2-year lag from the start of the intervention program. In the education communities, 2,394 cases of coronary heart disease and 818 cases of stroke occurred, with 2,526 and 739 cases, respectively, being seen in the comparison communities. The overall decline in coronary heart disease incidence was 1.8 percent per year in men (p = 0.03) and 3.6 percent per year in women (p = 0.007). For stroke, there were no significant secular trends. The authors recently published findings showing minimal effects of sustained intervention on risk factor levels. In the current report, there was no evidence of a significant intervention effect on morbidity or mortality, either for coronary heart disease or for stroke.

A qualitative study to explore the concept of fatigue/tiredness in cancer patients and in healthy individuals

Interest in fatigue research has grown since the finding that fatigue/tiredness is the most frequently reported symptom of cancer and its treatment. But even though several authors have tried to conceptualize fatigue (Piper & Rieger, 1989; Cimprich, 1992; Gibson & Edwards, 1985; Winningham, 1994; Irvine et al. 1994; Grandjean, 1970; et al.), its mechanisms are still poorly understood. The aim of this study was two-fold: i) to explore fatigue in cancer patients, inductively, and ii) to compare fatigue/tiredness experiences of healthy individuals with those of cancer patients to identify cancer-specific fatigue/tiredness and related concepts. A qualitative research strategy was adopted using a grounded-theory approach. The prospective study took place in the Oncology Department of the Kantonsspital St Gallen (Switzerland) with samples of 20 cancer patients and 20 healthy individuals. Unstructured, tape-recorded interviews were conducted to collect data. Transcripts of the interviews were analysed using content analysis and constant comparison. Although different themes emerged between the two groups, both fitted a classification system that categorized expression of fatigue/tiredness as physical, affective or cognitive. Physical signs were more frequent than affective and cognitive signs in both groups. For the cancer patients, fatigue involved decreased physical performance, extreme, unusual tiredness, weakness and an unusual need for rest, which was distinctly different for healthy persons. Affective and cognitive distress were also more prominent in cancer patients. Interestingly, the concept of malaise was not identified by either sample and not understood as an expression of fatigue by this German-speaking population. Linguistic differences in the description of fatigue/tiredness between healthy and ill individuals revealed different perceptions of the phenomenon. A step-like theory, involving nociception, perception and expression of tiredness, was put forward tentatively to explain the production of fatigue/tiredness. The emerging concepts break tiredness/fatigue into expressions of physical, affective and cognitive tiredness/fatigue. The experience is different between healthy individuals and cancer patients. The generalization of data needs precaution but the results of the study identify and clarify ideas that might form an important basis for further, controlled studies.

A qualitative study to explore the concept of fatigue/tiredness in cancer patients and in healthy individuals

Interest in fatigue research has grown since the finding that fatigue/tiredness is the most frequently reported symptom of cancer and its treatment. But even though several authors have tried to conceptualise fatigue, its mechanisms are still poorly understood. The aim of this study was twofold: (a) to explore fatigue in cancer patients inductively, and (b) to compare experiences of fatigue/tiredness of healthy individuals with those of cancer patients to identify cancer-specific fatigue/tiredness and related concepts. A qualitative research strategy was adopted using a grounded-theory approach. The prospective study took place in the oncology department of the Kantonsspital, St. Gallen, Switzerland, with samples of 20 cancer patients and 20 healthy individuals. Unstructured, tape-recorded interviews were conducted to collect data. The transcripts of the interviews were analysed using content analysis and constant comparison. Different themes emerged between the two groups although both fitted a classification system that categorised fatigue into physical, affective and cognitive expressions of fatigue/tiredness. Physical signs were more frequent than affective and cognitive signs in both groups. In the cancer patients, fatigue involved decreased physical performance, extreme, unusual tiredness, weakness and an unusual need for rest, which was distinctly different for healthy persons. Affective and cognitive distress was also more prominent in cancer patients. Interestingly, the concept of malaise was not identified by either sample and not understood as an expression of fatigue by this German-speaking population. Linguistic differences in the description of fatigue/tiredness between healthy and ill individuals revealed different perceptions of the phenomenon. A step-like theory, explaining the production of fatigue/tiredness was tentatively put forward involving nociception, perception and expression of tiredness. The emerging concepts break tiredness/fatigue into an expression of physical, affective and cognitive tiredness/fatigue. The experience is different between healthy individuals and cancer patients. Care must be taken when drawing generalised conclusions but the results of the study identify and clarify ideas that might form an important basis for further, controlled studies.

Information sources used in decision making: considerations for simulation development

Simulation tasks, together with think aloud techniques are often used to research the cognitive processes individuals go through when making a decision or solving a problem. They have been utilised to a certain degree within nursing. A study was carried out to try and identify the sources of information nurses in acute medical and surgical wards used to make assessment judgements. A sample of 114 nurses were interviewed, and their responses analysed using content analysis. Four main sources of information were identified, with verbal interaction being the source of information most frequently mentioned by the subjects. The content of material presented in simulations is normally tested using techniques such as expert panels. However, this paper suggests that of equal importance may be the form of presentation or source of that information. It is suggested that in order to increase the validity of information obtained from simulation tasks, the form of presentation of information to the subject should also be considered.

Categorisation of the patient's medical condition--an analysis of nursing judgement

This paper is a report of a study designed to explore the way in which community and hospital based nurses categorised 35 medical conditions. The results, obtained from a series of card-sorts using a Multiple Sorting Task and a modified Q-Sort, found that nurses used four global sub-categories of severity to categorise them. The findings provided a basis for an analysis of nursing assessment and established that they were realised as prognostic judgements. Discussion of the structure of the categories led to a possibility that the cognitive skill referred to as 'intuition' could be explained by the way in which clinical knowledge comes to be organised in memory.

Comparison of experimental and theoretical parameters of the Moolgavkar-Venzon-Knudson incidence function for the stages of initiation and promotion in rat hepatocarcinogenesis

Mathematical descriptions of complex biological phenomena, such as cancer, require an experimental format that faithfully recapitulates the biological process. In addition, the biological process must dictate the parameters in the mathematical formula. Evidence from the epidemiology of several human cancers and from experimental carcinogenesis in several organ systems indicates that cancer is a multistage process. The initiation-promotion-progression format of experimental carcinogenesis mimics the development of cancer in humans and other animals. In rats, the altered hepatic focus model of hepatocarcinogenesis has been well characterized and, coupled with the method of quantitative stereology, permits accurate determination of the number and the volume fraction of such altered foci per liver. The placental isozyme of glutathione S-transferase (PGST) is reportedly the best single marker of preneoplasia in the rat liver. Recently, single hepatocytes expressing PGST have been proposed as putatively initiated cells. Quantitation of individual hepatic cells and altered hepatic foci expressing PGST in the livers of rats subjected to an initiation-promotion protocol permits determination of the congruence of the Moolgavkar-Venzon-Knudson (MVK) model with experimental data. The best fit of the MVK model for the preneoplastic stages of hepatocarcinogenesis assumes that all hepatocytes are susceptible and that single hepatocytes expressing PGST are the initiated cell population for the focal lesions that express PGST. Further refinement of the initiation-promotion-progression model to permit accurate quantitation of early malignant conversion should allow a more complete analysis of the congruence of the MVK model for human cancer risk determination. In addition, the MVK model may be extended to other model systems and to human cancers in which early preneoplasia can be quantitated. Furthermore, the use of a more biologically based risk-assessment protocol, such as the MVK model rather than the stochastic one-hit model presently used, would permit incorporation of the present knowledge on the pathogenesis of cancer. To apply experimental data to a mathematical model that reflects the biological processes underlying human cancer development will require integration of the cell kinetics and experimental data to a mathematical model that reflects the biological processes underlying human cancer development including the pharmacokinetic and pharmacodynamic properties of the treatment chemicals.

Community education for cardiovascular disease prevention: risk factor changes in the Minnesota Heart Health Program

OBJECTIVES

The Minnesota Heart Health Program is a 13-year research and demonstration project to reduce morbidity and mortality from coronary heart disease in whole communities.

METHODS

Three pairs of communities were matched on size and type; each pair had one education site and one comparison site. After baseline surveys, a 5- to 6-year program of mass media, community organization, and direct education for risk reduction was begun in the education communities, whereas surveys continued in all sites.

RESULTS

Many intervention components proved effective in targeted groups. However, against a background of strong secular trends of increasing health promotion and declining risk factors, the overall program effects were modest in size and duration and generally within chance levels.

CONCLUSIONS

These findings suggest that even such an intense program may not be able to generate enough additional exposure to risk reduction messages and activities in a large enough fraction of the population to accelerate the remarkably favorable secular trends in health promotion activities and in most coronary heart disease risk factors present in the study communities.

Incorporation of bromodeoxyuridine in glutathione S-transferase-positive hepatocytes during rat multistage hepatocarcinogenesis

Cell proliferation is pivotal to all stages of the carcinogenesis process and is one of the primary characteristics of the promotion stage of cancer development. Both a two-stage model of initiation and promotion for analysis of early preneoplasia and a three-stage initiation-promotion-progression model of hepatocarcinogenesis were used to address the effect of the liver tumor-promoting agent phenobarbital (PB) on hepatic cellular proliferation. Male rats were subjected to a 70% partial hepatectomy and 10 mg diethylnitrosamine (DEN)/kg or the solvent alone and were administered PB for 4-8 months. Analysis of bromodeoxyuridine (BrdU) incorporation (1 h pulse) in liver within (focal) and not within (non-focal) altered hepatic foci (AHF) demonstrated a labeling index in AHF of 2% in DEN-initiated rats; the non-focal labeling index of placental glutathione S-transferase expressing hepatocytes was 0.3-0.6%. The focal labeling index was constant over the 8 month period of promotion. Inasmuch as one characteristic of promotion is the reversibility of the induced effects on clonal expansion of initiated cells, groups of rats initially promoted with PB were maintained in the absence of continued promotion for 4 or 8 months prior to being killed. Assessment of the focal labeling index after cessation of PB treatment indicated a drop in the index from 2.3% to 0.7%. When a progressor agent, ethylnitrosourea, was given at the time PB was discontinued for 4 or 8 months, a significant change in focal labeling index was not observed relative to the index in AHF when the animals were killed immediately after 8 months of PB promotion. Thus, cell proliferation plays an integral role in both the promotion and progression stages of multistage rat hepatocarcinogenesis and is influenced by administration of promoting and progressor agents.

Black-white differences in electrocardiographic left ventricular mass and its association with blood pressure (the ARIC study). Atherosclerosis Risk in Communities

Black-white differences in the association between antihypertensive therapy, continuous measures of mean arterial and pulse pressures and left ventricular (LV) mass estimated from a multivariable electrocardiographic algorithm were examined in 6,020 men (23% black) and 7,970 women (29% black) participating in the Atherosclerosis Risk in Communities (ARIC) study. Mean arterial and pulse pressures, weight, the percentage of subjects taking antihypertensive medication, and LV mass were higher in black than in white men (98 vs 89 mm Hg, 47 vs 46 mm Hg, 188 vs 187 pounds, 30% vs 17%, and 243 vs 217 g, respectively). Results of similar direction but greater magnitude were observed in black versus white women (mean arterial pressure, 94 vs 85 mm Hg; pulse pressure, 50 vs 47 mm Hg; weight, 180 vs 153 pounds; percent treated, 42% vs 18%; and LV mass, 203 vs 169 g, respectively). In multivariable regression analyses, blacks had higher levels of LV mass, and LV mass increased more sharply with increasing mean arterial pressure in blacks than in whites after adjusting for age, pulse pressure, and weight. At equal mean arterial and pulse pressures, age, and weight, treated blacks had higher LV mass than treated whites. These data indicate that blacks have higher LV mass than whites, and a more pronounced blood pressure-LV mass relation after controlling for other risk factors and treatment status. Given the prognostic importance of LV hypertrophy,

Intermittent ST depression and mortality after myocardial infarction

BACKGROUND

We conducted a case-control analysis to determine the contribution made to mortality by intermittent ST depression (STD) among patients enrolled in the already completed Beta Blocker Heart Attack Trial.

METHODS AND RESULTS

STD was determined by computer analysis of 24-hour ECG tapes as a change in ST level by +/- 0.1 mV or more from the median value of ST of all normally conducted complexes for greater than or equal to 1 minute. All computer-detected ST events were verified by trained readers. To estimate risk of dying associated with STD, 261 deaths were compared with controls matched for age, sex, drug status, and time elapsed since acute myocardial infarction. In a model including relevant covariates, STD had a relative risk (RR) of 1.73 (95% confidence interval, 1.09-2.73). The RR was 2.56 (1.39-4.71) in untreated patients and 0.98 (0.48-2.00) in propranolol-treated patients. A history of angina, although not independently significant, was found to enhance these RRs. A gradient of risk was shown in the placebo group by a RR of 1.91 in those with 1-30 minutes of STD and 4.33 in those with greater than 30 of STD (p = 0.001, trend test).

CONCLUSIONS

The findings in this large study show a significant contribution to mortality among untreated early post-myocardial infarction survivors from transient STD on 24-hour monitoring. The absence or reduction of effect in the treated group also suggests an anti-ischemic mechanism by which propranolol exerts a protective effect on mortality. Trials to determine whether reduction of STD improves survival would be warranted.

Symptom-limited graded treadmill exercise testing in young adults in the CARDIA study

Symptom-limited, graded exercise treadmill testing was performed by 4,968 white and black adults, ages 18-30 yr, during the baseline examination for the CARDIA study. The mean estimated maximal exercise capacity by race/gender, expressed as metabolic units (METS), was: white men 13.8, black men 13.0, white women 11.1, and black women 9.4. Exercise test duration was higher in nonsmokers, positively related to physical activity score and pulmonary function (FEV1.ht-2), and inversely related to body mass index. Men had higher mean values than women for both test duration and a measure of submaximal performance, the workload 130 (WL130, the exercise test duration to a heart rate of 130 beats.min-1). Adjusted for age and education, white men had a longer mean test duration than black men (53 s longer, P less than 0.001), but nearly equal mean WL130. White women had higher mean values than black women for both test duration (114 s longer, P less than 0.001) and WL130 (36 s longer, P less than 0.001). Men had higher mean values than women for both outcome measures (P less than 0.001). Thus, in young adults significant gender and ethnic differences exist for exercise test performance, part of which can be explained by personal habits or traits.

Secular trends in Q wave and non-Q wave acute myocardial infarction. The Minnesota Heart Survey

The Minnesota Heart Survey examined trends of Q wave and non-Q wave acute myocardial infarction (AMI) using a 50% random sample of all hospital discharges of patients with AMI or another acute coronary disease from 35 of 36 hospitals in 1970 and 30 of 31 hospitals in 1980 in the Minneapolis-St. Paul metropolitan area. A total of 1,901 and 1,864 potential AMI cases were abstracted in 1970 and 1980, respectively. Electrocardiograms were coded according to the Minnesota code. AMIs were validated by computerized algorithm based on chest pain, enzymes, electrocardiograms, and autopsy. This study shows that with the use of a consistent, standard diagnostic algorithm, attack rates for Q wave AMI did not change significantly between 1970 and 1980 and that attack rates for non-Q wave AMI decreased significantly during the same decade. However, when the more sensitive cardiac enzymes creatine phosphokinase and creatine phosphokinase-MB were considered, attack rates of both Q wave and non-Q wave AMIs increased. This research documents four important trends for community AMI rates that are at variance with those reported by others. There was a decline in non-Q wave AMI attack rates from 1970 to 1980; women had outcomes equal to or worse than those for men for both case-fatality and 7-year survival rates; patients with non-Q wave AMIs had worse in-hospital prognoses than those with Q wave AMIs; and 7-year survival rates were worse for Q wave AMI in 1980. These findings demonstrate the need for standard diagnostic criteria for Q wave and non-Q wave AMI if trends are to be monitored. In the future, as new trials of operative and nonoperative therapies of AMI are undertaken, these considerations will increase in importance.

The effect of the number of electrocardiograms analyzed on cardiovascular disease surveillance: the Minnesota Heart Survey (MHS)

One method used to control costs in community cardiovascular disease surveillance is to limit the number of electrocardiograms (ECGs) used to validate acute myocardial infarction (AMI). The Minnesota Heart Survey investigated the impact of decreasing the maximum number of ECGs analyzed on classification of ECG pattern and final AMI diagnosis (definite, probable, none). A 50% sample of all 1980 acute CHD hospital discharge records (ICD-9 code 410 or 411) from 30 of 31 Twin Cities hospitals were abstracted. Comparing results using all available ECGs in the record (maximum of 12) with those obtained using up to 4 ECGs showed little differences in the ECG classification or final AMI diagnosis.

Cardiac status after four years in a trial on nutritional therapy for high blood pressure

A randomized controlled trial demonstrated the ability of nutritional intervention in place of antihypertensive drugs to maintain blood pressure at normal levels for four years in 39% of less severely hypertensive patients whose blood pressure was previously well controlled by pharmacologic treatment. However, average blood pressures during the trial for patients in the intervention group were higher than those for a comparison group that continued to receive drug therapy throughout the study. Holter monitoring, echocardiography, roentgenography, and electrocardiography done at four years to determine whether blood pressure differences between groups were associated with differences in cardiac status did not indicate any differences in cardiac status favorable to one group compared with the other. Further investigation in larger samples is needed to assess any long-term differences in cardiac status based on such alternate therapies.

Electrocardiographic left ventricular hypertrophy and effects of antihypertensive drug therapy in hypertensive participants in the Multiple Risk Factor Intervention Trial

Data are reported on electrocardiographic left ventricular hypertrophy (ECG LVH) among 8,012 men classified as hypertensive at baseline in the Multiple Risk Factor Intervention Trial. Compared with those allocated to the usual care (UC) control group, men allocated to the special intervention (SI) group experienced a mean reduction of 4 mm Hg in diastolic blood pressure and 7 mm Hg in systolic blood pressure, over 6 years of follow-up. There were 378 new cases of ECG LVH during follow-up; the incidence in the SI group was about 23% less than that in the UC group (4.2 vs 5.4% 2P less than 0.01). Among the 189 men with ECG LVH at baseline, those in the SI group experienced about 24% more annual follow-up visits at which they were free of ECG LVH (4.6 vs 3.7 visits; 2P less than 0.01). This reduced incidence and increased reversal of ECG LVH in the SI group compared with that in the UC group was consistent with significant overall reductions (2P less than 0.001) among SI men in mean wave amplitude in those leads in which voltage is correlated with left ventricular mass (T wave in V1, R wave in aVL and S wave in V3). In SI and UC groups combined, the presence of ECG LVH either at baseline or at follow-up was associated with several-fold increases in death from cardiovascular diseases in general, and death from coronary artery disease in particular.(ABSTRACT TRUNCATED AT 250 WORDS)

Indwelling catheterization and related nursing practice

A survey of patients with an indwelling urethral catheter was conducted over a 14-day period in five randomly selected district general hospitals in England. The demographic characteristics of the patients and the types of catheter and urinary drainage bags used were recorded. Observational techniques were used to describe nursing care during meatal cleansing and bag emptying Over the 14-day study period 294 patients were catheterized giving an overall daily incidence of catherization of 11.2 per 1000 of the average daily population. Nurses inserted over 50% of catheters and subsequently maintained all closed urinary drainage systems. The closed system was broken for 42% of patients and only 48% of drainage bags were always observed in the correct position. Techniques aimed at preventing infection were observed more frequently when meatal cleansing was performed separately from daily hygiene. The frequency of hand washing, both before and after meatal cleansing and bag emptying, was low. It is concluded that the procedures and practices involved in the care of the urinary drainage system require re-evaluation and re-emphasis.

Systolic blood pressure as an independent predictor of mortality in the Hypertension Detection and Follow-up Program

The Hypertension Detection and Follow-up Program (HDFP) findings demonstrate the predictive value of baseline systolic blood pressure (SBP) and of pulse pressure (PB) in five-year mortality from all causes. Grouping participants into four SBP strata revealed an approximately two-fold increase in age-adjusted mortality rate from SBP stratum I to SBP stratum IV. This effect remained after the contributions of other risk factors were controlled by multivariate analysis. In contrast, baseline diastolic blood pressure (DBP) had little demonstrable effect on mortality in this particular population. The predictive power of pulse pressure was similar to that of SBP. The group mean SBP of every stratum fell progressively during the trial, the change being of greater magnitude in the stepped care (SC) group than in the referred care (RC) group. Also, the reduction in all-cause mortality associated with SC treatment was observed at all levels of baseline SBP. An analysis using life table regression with SBP as a time-dependent variable showed that the postrandomization reduction in SBP was a significant factor in reducing mortality. Similarly, reduced DBP was also contributory. Prospective studies are required to answer definitively the question of the efficacy of treatment of systolic hypertension. Nevertheless, the present analysis of the HDFP data, despite design limitations, supports the advisability of reducing elevated systolic blood pressure.

Frontiers of nursing in the twenty-first century: development of models and theories on the concept of nursing

Theories and models on the concept of nursing are reviewed briefly and their contribution then assessed in terms of their potential to advance the scientific basis of nursing practice. The constructs are acknowledged to have moved the focus of nursing from disease to patient need and provided different ways of looking at the nurse's contribution. Yet, despite this advance, the constructs have not been put to the rigours of scientific testing and so remain at the level of speculation. Therefore, towards the developments for the twenty-first century it is proposed that these ideas should be put to the test to establish their relevance in the real world of nursing care. This requires: a framework from which the nature, extent and purpose of care can be specified; independent criteria which can be used to judge effectiveness of care; knowledge as it relates to the different and varied core concepts underlying the practice of nursing; and a working definition of need. In addition, the extent of care for the community needs to be made explicit through research. Together, this represents a challenge to develop theories which are logically related to single core concepts which themselves represent specific areas of actual nursing practice.

Ventricular premature contractions: a randomized non-drug intervention trial in normal men

The influence of a 6-week intervention on factors thought to be related to ectopic cardiac rhythms was tested in normal men with frequent ventricular premature contractions (VPCs), using a randomized, controlled and partial crossover design. The VPC intervention trial experimental regimen included total abstinence from caffeine and smoking, reduction of alcohol intake, and a physical conditioning program. Effects were studied in detail among 81 healthy men with persistent VPCs. VPCs were measured during standard states of rest, dynamic and isometric exercise and other stresses, and 24-hour ambulatory monitoring. Adherence to the treatment was excellent. The experimental group achieved more than 80% of activities asked of them, and little "contamination" occurred in the control group. VPCs were analyzed according to VPC/min, VPC/man and VPC/total number of heart beats. Moderate changes in VPC rates occurred in both experimental and control groups but no significant group differences were found at rest or during any induction test. This 6-week, multiple-factor "hygienic" intervention program had no significant influence on the frequency or occurrence of VPCs in apparently normal men with persistent and frequent VPCs. Because the mechanisms and the significance of VPCs are different in patients with ischemic heart disease, our approach and methods may be useful for similar trials among cardiac patients of adjunct or non-drug therapy for ectopic rhythms.