Risk Of Nonfatal Myocardial Infarction Research Articles

Vitamins for the management of cardiovascular disease: a simple solution to a complex problem?

Attention is focusing on the relationship between homocysteine and cardiovascular disease and the role of vitamins in the management of this prevalent ailment. Epidemiologic studies have shown that a relationship between elevated homocysteine concentrations and cardiovascular disease may exist; however, a cause-and-effect relationship has not been proven. The B vitamins are key components of homocysteine metabolism, and the trend is toward their being increasingly prescribed for cardiovascular disease. Prescribing of antioxidant vitamins, vitamin E in particular, has increased as well. Vitamin E may decrease the risk of nonfatal myocardial infarction in patients with coronary artery disease, but its benefit in preventing fatal myocardial infarction has not been shown. Vitamin supplements are not warranted in all patients with cardiovascular disease but may have a place in therapy for selected patients.

Angiotensinogen T174M and M235T gene polymorphisms are associated with the extent of coronary atherosclerosis

Background: The relations of the angiotensinogen (AGT) T174M and M235T gene polymorphisms to the risk of coronary heart disease (CHD) have been investigated in only a few studies with conflicting results. Results: Therefore, we analysed the relationship of the AGT gene polymorphisms to the presence and extent of CHD in 2250 male Caucasians whose coronary anatomy was defined by means of coronary angiography. The relative frequencies of the T and M alleles of the T174M and of the M235T gene variation did not significantly differ between patients without or with single-, double- or triple-vessel disease and between subjects without or with myocardial infarction (MI). In contrast the mean CHD score–defined by Gensini–was higher within MM homozygotes of the T174M gene variation than within TT genotypes; TM subjects had intermediate values. In M235T genotypes, mean CHD scores were similar in the total sample and in older individuals (≥62 years), whereas in younger individuals (<62 years) a higher CHD score was found within AGT 235 T allele carriers than within MM homozygotes. In younger individuals with high apoAI plasma levels, the mean CHD score was clearly higher within TT homozygotes of the M235T gene variation than within MM genotypes; MT subjects had intermediate values. An interaction between both angiotensinogen gene polymorphisms on the extent of CHD or on the risk of non-fatal MI were not observed when the M allele of AGT T174M was combined either with the T allele or the TT genotype of M235T. Conclusions: The present study strengthens the hypothesis of an association of both angiotensinogen gene polymorphisms with the extent of coronary heart disease.

Angina and its treatment.

Angina and its treatment.

Update on aspirin in the treatment and prevention of cardiovascular disease

The effects of low-dose aspirin on cardiovascular disease have been tested in randomized trials in 3 types of populations: (1) patients with a history of cardiovascular disease; (2) patients with evolving acute myocardial infarction (MI), and (3) apparently healthy subjects. In a very wide range of patients with prior occlusive cardiovascular disease, aspirin reduces the risks of nonfatal MI, nonfatal stroke, and vascular death. Initiating aspirin therapy within 24 hours after the onset of symptoms of an acute MI also confers conclusive reductions in the risk of nonfatal reinfarction, nonfatal stroke, and total cardiovascular death. In primary prevention trials, aspirin has been shown to reduce the risk of a first MI in men, but the data on stroke and total cardiovascular death are not sufficient to allow firm conclusions to be drawn; randomized data from studies in women are not yet available. The Women’s Health Study, an ongoing large-scale trial in female health care professionals, will provide the data necessary to assess the balance of benefits and risks of aspirin in primary prevention. Until then, the decision to use aspirin in primary prevention should be based on the clinical judgment of the physician and considered as an adjunct in the management of other cardiovascular disease risk factors. (Am Heart J 1999;137:S9-S13.)

Body weight and weight gain during adult life in men in relation to coronary heart disease and mortality A prospective population study

To assess the risk of death from coronary disease, and all causes associated with body mass index and weight gain from age 20 to middle age. In this study, 6874 men aged 47 to 55 years at baseline and free of a history of myocardial infarction were followed with respect to mortality from coronary disease and from all causes over an average follow-up of 19.7 years, and with respect to non-fatal myocardial infarction for 11.8 years. High body mass index predicted death from coronary disease, but only at levels above 27.5 m.kg-2. Men with stable weight (defined as +/- 4% change from age 20) had the lowest death rate from coronary disease and the lowest risk of non-fatal myocardial infarction. Relative risk of coronary death increased with increasing weight gain, from 1.57 (1.14-2.15) (after adjustment for age, physical activity, and smoking) in the group who gained 4 to 10%, to 2.76 (1.97-3.85) in men with a weight gain of more than 35% (P for trend 0.0001), compared to men who remained stable. After further adjustment for serum cholesterol, systolic blood pressure, and diabetes, relative risks were reduced but still significantly elevated in all weight gain groups (P for trend 0.004). Data concerning non-fatal myocardial infarction were available for the first 11.8 years and showed a relative risk of 3.35 (2.05-5.47) after adjustment for age, physical activity, and smoking in men with a weight gain of more than 35%. Weight gain from age 20, even a very moderate increase, is strongly associated with an increased risk of coronary death and non-fatal myocardial infarction.

Haemostatic factors and prediction of ischaemic heart disease and stroke in claudicants.

Thrombotic risk factors may be important in determining cardiovascular outcome in patients with symptomatic peripheral arterial disease. A cohort study with a 6-year follow-up period was established to determine the relationships between haemostatic and rheological factors and incident ischaemic heart disease (IHD) and stroke events in patients with peripheral arterial disease. A consecutive series of 607 patients with intermittent claudication was examined between 1989 and 1990 at the Peripheral Vascular Clinic, Royal Infirmary of Edinburgh. Main outcome measures were combined fatal and non-fatal stroke, non-fatal myocardial infarction (MI), coronary death and total coronary events. A total of 210 patients died during follow-up. 203 patients did not experience a vascular event or deterioration of limb ischaemia. Median levels of fibrinogen, von Willebrand factor (VWF), tissue plasminogen activator (t-PA) antigen, fibrin D-dimer and whole blood viscosity were significantly higher in those who experienced an event compared with those who did not. After adjusting for age and sex, fibrin D-dimer was significantly associated with risk of non-fatal myocardial infarction (RR 1.50, 95% CI 1.09-2.06, P < or = 0.01). Both fibrinogen and fibrin D-dimer were associated with risk of total coronary events (P < or = 0.05). The risk of stroke was related to baseline levels of t-PA antigen (RR 1.87, 95% CI 1.04-3.34, P < or = 0.05) and whole blood viscosity (RR 1.33, 95% CI 1.07-1.65, P < or = 0.01). All the relationships became weaker and statistically non-significant after further adjustment for cigarette smoking, systolic blood pressure, glucose and baseline IHD. The associations of these factors to IHD and stroke may therefore be partly related to cardiovascular risk factors, but are likely to be important in the pathogenesis of future atherothrombotic events in subjects with peripheral arterial disease.

Incremental prognostic value of myocardial perfusion single photon emission computed tomography for the prediction of cardiac death: differential stratification for risk of cardiac death and myocardial infarction.

The incremental prognostic value of stress single photon emission computed tomography (SPECT) for the prediction of cardiac death as an individual end point and the implications for risk stratification are undefined. We identified 5183 consecutive patients who underwent stress/rest SPECT and were followed up for the occurrence of cardiac death or myocardial infarction. Over a mean follow up of 642+/-226 days, 119 cardiac deaths and 158 myocardial infarctions occurred (3.0% cardiac death rate, 2.3% myocardial infarction rate). Patients with normal scans were at low risk (< or =0.5%/y), and rates of both outcomes increased significantly with worsening scan abnormalities. Patients who underwent exercise stress and had mildly abnormal scans had low rates of cardiac death but higher rates of myocardial infarction (0.7%/y versus 2.6%/y; P<.05). After adjustment for prescan information, scan results provided incremental prognostic value toward the prediction of cardiac death. The identification of patients at intermediate risk of nonfatal myocardial infarction and low risk for cardiac death by SPECT may result in significant cost savings when applied to a clinical testing strategy. Myocardial perfusion SPECT yields incremental prognostic information toward the identification of cardiac death. Patients with mildly abnormal scans after exercise stress are at low risk for cardiac death but intermediate risk for nonfatal myocardial infarction and thus may benefit from a noninvasive strategy and may not require invasive management.

Hostility, aggression and the risk of nonfatal myocardial infarction in postmenopausal women

Hostility can predict coronary heart disease (CHD) and total mortality in men. However, in women this association has not been as thoroughly explored. This study examines whether hostile and aggressive attitudes are associated with myocardial infarction (MI) in postmenopausal women. Cases included 277 women who presented with an incident MI. Controls included a random sample of 988 female health maintenance organization enrollees. Women were asked the Hostile-Affect and the Aggressive-Responding factors of the Cook-Medley Hostility Scale. The Hostile-Affect score was linearly associated with increased risk for MI (odds ratio [OR] per point = 1.22; 95% confidence interval [CI 95%]=1.07−1.38), whereas the Aggressive-Responding score had a modest protective effect (OR=0.92 per point; CI 95%=0.84−1.02); p=0.009. Adjustment for sociodemographic and MI risk factors altered these results only slightly. These hostility measures are easily administered, and could help to identify women who are at high risk for CHD and who may benefit from preventive measures.

Alpha-tocopherol may reduce the risk of non-fatal myocardial infarction among patients with angiographically proven coronary atherosclerosis

Alpha-tocopherol may reduce the risk of non-fatal myocardial infarction among patients with angiographically proven coronary atherosclerosis

Use of ankle brachial pressure index to predict cardiovascular events and death: a cohort study.

To determine whether a low ankle brachial pressure index is associated with an increased risk of cardiovascular events and death, and whether the prediction of such events could be improved by including this index. Cohort study. 11 practices in Edinburgh, Scotland. 1592 men and women aged 55-74 years selected at random from the age-sex registers of 11 general practices and followed up for 5 years. Incidence of fatal and non-fatal cardiovascular events and all cause mortality. At baseline 90 (5.7%) of subjects had an ankle brachial pressure index < or = 0.7, 288 (18.2%) had an index < or = 0.9, and 566 (35.6%) < or = 1.0. After five years subjects with an index < or = 0.9 at baseline had an increased risk of non-fatal myocardial infarction (relative risk 1.38, 95% confidence interval 0.88 to 2.16), stroke (1.98, 1.05 to 3.77), cardiovascular death (1.85, 1.15 to 2.97), and all cause mortality (1.58, 1.14 to 2.18) after adjustment for age, sex, coronary disease, and diabetes at baseline. The ability to predict subsequent events was greatly increased by combining the index with other risk factors--for example, hypertensive smokers with normal cholesterol concentrations had a positive predictive value of 25.0%, increasing to 43.8% in subjects with a low index and decreasing to 15.6% in those with a normal index. The ankle brachial pressure index is a good predictor of subsequent cardiovascular events, and improves on predictions by conventional risk factors alone. It is simple and accurate and could be included in routine screening of cardiovascular status.

Triggering Myocardial Infarction by Sexual Activity

Objective. —To determine the relative risks of nonfatal myocardial infarction (MI) triggered by sexual activity among the general population and in patients with prior coronary heart disease. Design. —Relative risks and effect modification were calculated by the case-crossover method, a new epidemiologic technique designed to quantify the transient change in risk following exposure to a potential disease trigger. Setting/Participants. —A total of 1774 patients with MI were interviewed in 45 hospitals throughout the United States. Data were gathered on potential triggers of MI occurring immediately prior to the event and during the previous year. Results are presented for the 858 patients who were sexually active in the year prior to the Ml, with attention to the 273 patients who had coronary artery disease prior to their index Ml, and the effect of regular exertion on risk. Main Outcome Measure. —The relative risk of nonfatal MI following sexual activity. Results. —Of the 858 patients, 79 (9%) reported sexual activity in the 24 hours preceding Ml, and 27 (3%) reported sexual activity in the 2 hours preceding onset of symptoms of MI. The relative risk of MI occurring in the 2 hours after sexual activity was 2.5 (95% confidence interval [CI], 1.7-3.7). The relative risk of triggering onset of Ml among patients with a history of prior angina (2.1 [95% CI, 0.8-5.8]) or prior Ml (2.9 [95% CI, 1.3-6.5) was not greater than that observed in those without prior cardiac disease. Sexual activity was a likely contributor to the onset of Ml in only 0.9% of cases and regular exertion was associated with decreasing risk. Conclusions. —Sexual activity can trigger the onset of MI. However, the relative risk is low, and since the absolute hourly risk of MI is extremely low, the absolute risk increase caused by sexual activity also is extremely low (1 chance in a million for a healthy individual). Moreover, the relative risk is not increased in patients with a prior history of cardiac disease and regular exercise appears to prevent triggering. These findings should be useful for counseling patients and decreasing the fear of sexual activity that often prevents complete rehabilitation from cardiovascular disease. ( JAMA . 1996;275:1405-1409)

Influence of fathers' social class on cardiovascular disease in middle-aged men

The independent effect of early life circumstances on adult cardiovascular risk is still unresolved. We assessed the associations of father's social class with cardiovascular risk factors and with risk of ischaemic heart disease and stroke in adult life. We did a longitudinal study of cardiovascular disease in 5934 men aged 40-59 years at enrollment. A cross-sectional measurement survey was done between 1978 and 1980 and a follow-up questionnaire was completed in 1992. The main endpoints were non-fatal myocardial infarction and stroke based on general practitioners' reports obtained between screening and 1992 and on recall of physician-diagnosed ischaemic heart disease in the 1992 questionnaire. Father's social class was strongly associated with social class in adulthood (fathers' occupation was manual for 41.3% of professionals [I] vs 89.1% for unskilled manual workers [V]) and was significantly related to height (non-manual vs manual 175.4 cm [SE 0.2] vs 172.9 cm [0.1], p < 0.0001) and obesity (213 [14.1%] vs 804 [20.1%], p < 0.0001) irrespective of adult social class; no association was found with blood glucose (log, 1.69 [0.005] vs 1.70 [0.003], p = 0.22) or cholesterol (6.34 [0.03] vs 6.29 mmol/L [0.02], p = 0.16. Men whose fathers' social class was manual had significantly higher rates of non-fatal myocardial infarction (342/4006 vs 92/1510) and self-reported physician-diagnosed ischaemic heart disease (686/4006 vs 192/1510) than men whose fathers' social class was non-manual, even after adjustment for adult social class and other established risk factors (relative odds 1.3 [95% Cl 1.0-1.7], p < 0.05 and 1.3 [1.1-1.6], p < 0.01, respectively). The influence of father's social class on non-fatal myocardial infarction and ischaemic heart disease was only seen in men whose adult social class was non-manual. No association was seen between father's social class and non-fatal stroke. Father's social class is strongly associated with adult social class. The higher risk of non-fatal myocardial infarction and self-reported physician-diagnosed ischaemic heart disease seen in men whose father's social class was manual suggests that socioeconomic status early in life has some persisting influence on ischaemic heart disease risk in adult life.

Diet-heart issues in a pharmacological era

Reduction of serum cholesterol low-density lipoprotein (LDL) is an important step in secondary and primary prevention of coronary heart disease, and clinical trials have now shown that cholesterol lowering drugs substantially lessen coronary risk within a few years? These findings will undoubtedly increase the popularity of cholesterol lowering by drugs at the expense of dietary modification. However, properly applied dietary changes should be the first step in cholesterol lowering. In this short overview I focus on two elements of a healthy-heart diet--fatty acids and antioxidants. Fatty acids are a major determinant of serum cholesterol and LDL concentrations. Antioxidants may prevent oxidative modification of LDL, which is an important step in the development of atherosclerosis. I also discuss the effectiveness of dietary intervention.

Relation between Intake of Flavonoids and Risk for Coronary Heart Disease in Male Health Professionals

Flavonols and flavones are subgroups of flavonoids and are found in tea, vegetables, fruits, and red wine. Because they have antioxidant properties, we investigated whether intake of these dietary compounds is associated with a lower risk for fatal and nonfatal coronary heart disease. Prospective cohort study. United States. 34,789 male health professionals, 40 to 75 years of age, who responded to a questionnaire in 1986. In 1986 and 1990, detailed, 131-item questionnaires were used to assess dietary intake of flavonols and flavones. Between 1986 and 1992, 496 patients received a new diagnosis of nonfatal myocardial infarction. The relative risk for nonfatal myocardial infarction was 1.08 (95% Cl, 0.81 to 1.43) for the highest (median, 40.0 mg/d) compared with the lowest (median, 7.1 mg/d) quintiles for intake of flavonols and flavones after adjustment for age, obesity, smoking, intake of vitamin E, intake of alcohol, diabetes, hypertension, hypercholesterolemia, and family history of coronary heart disease. Among the 4814 men who reported that they had previously had coronary heart disease, we found a modest but nonsignificant inverse association between intake of flavonols and flavones and subsequent coronary mortality rates (relative risk, 0.63 [Cl, 0.33 to 1.20] for the highest compared with the lowest quintile for intake of flavonoids). The data do not support a strong inverse association between intake of flavonoids and total coronary heart disease, but they do not exclude the possibility that flavonoids have a protective effect in men with established coronary heart disease.

Ninety-day follow-up of patients in the emergency department with chest pain who undergo initial single-photon emission computed tomographic perfusion scintigraphy with technetium 99m-labeled sestamibi

Background. Patients in the emergency department with typical chest pain and a normal or nondiagnostic electrocardiogram have a 10% to 20% risk of nonfatal myocardial infarction. These patients can be stratified into groups of very low and very high risk for inpatient adverse cardiac events on the basis of initial 99mTc-labeled sestamibi single-photon emission computed tomographic (SPECT) perfusion imaging performed during symptoms. However, the intermediate or posthospital discharge prognosis of such patients has not been reported. Methods and Results. Patients ( n = 150) with typical chest pain (based on a semiquantitative chest pain questionnaire) and a normal or nondiagnostic electrocardiogram underwent injection of 15 to 45 mCi 99mTc-labeled sestamibi injected during symptoms. Ninety-day follow-up history (telephone questionnaire and review of medical records) was obtained in 140 patients, and follow-up electrocardiography was performed in 72 patients. Cardiac events (death, nonfatal myocardial infarction, thrombolysis, percutaneous transluminal coronary angioplasty, or coronary artery bypass grafting) occurred before hospital discharge in 33 patients (18%), and these patients were excluded from further analysis. At follow-up, two (8%) of 25 patients with an abnormal initial scintigram and none of 87 patients with a normal scan had cardiac events ( p = 0.008). Conclusions. In patients with typical angina and a normal or nondiagnostic electrocardiogram, initial SPECT scintigraphy allows early accurate risk stratification. The previously observed excellent inpatient prognosis of patients with a normal scintigram appears to extend for at least 90 days of follow-up. These observations may provide a rational basis for safe and cost-effective outpatient evaluation of selected patients in the emergency department with typical angina, a normal or nondiagnostic electrocardiogram, and a normal initial 99mTc-labeled SPECT perfusion scintigram performed during symptoms.

Triggering Myocardial Infarction by Sexual Activity

Objective. —To determine the relative risks of nonfatal myocardial infarction (MI) triggered by sexual activity among the general population and in patients with prior coronary heart disease. Design. —Relative risks and effect modification were calculated by the case-crossover method, a new epidemiologic technique designed to quantify the transient change in risk following exposure to a potential disease trigger. Setting/Participants. —A total of 1774 patients with MI were interviewed in 45 hospitals throughout the United States. Data were gathered on potential triggers of MI occurring immediately prior to the event and during the previous year. Results are presented for the 858 patients who were sexually active in the year prior to the Ml, with attention to the 273 patients who had coronary artery disease prior to their index Ml, and the effect of regular exertion on risk. Main Outcome Measure. —The relative risk of nonfatal MI following sexual activity. Results. —Of the 858 patients, 79 (9%) reported sexual activity in the 24 hours preceding Ml, and 27 (3%) reported sexual activity in the 2 hours preceding onset of symptoms of MI. The relative risk of MI occurring in the 2 hours after sexual activity was 2.5 (95% confidence interval [CI], 1.7-3.7). The relative risk of triggering onset of Ml among patients with a history of prior angina (2.1 [95% CI, 0.8-5.8]) or prior Ml (2.9 [95% CI, 1.3-6.5) was not greater than that observed in those without prior cardiac disease. Sexual activity was a likely contributor to the onset of Ml in only 0.9% of cases and regular exertion was associated with decreasing risk. Conclusions. —Sexual activity can trigger the onset of MI. However, the relative risk is low, and since the absolute hourly risk of MI is extremely low, the absolute risk increase caused by sexual activity also is extremely low (1 chance in a million for a healthy individual). Moreover, the relative risk is not increased in patients with a prior history of cardiac disease and regular exercise appears to prevent triggering. These findings should be useful for counseling patients and decreasing the fear of sexual activity that often prevents complete rehabilitation from cardiovascular disease. ( JAMA . 1996;275:1405-1409)

Triggering myocardial infarction by sexual activity. Low absolute risk and prevention by regular physical exertion. Determinants of Myocardial Infarction Onset Study Investigators.

To determine the relative risks of nonfatal myocardial infarction (MI) triggered by sexual activity among the general population and in patients with prior coronary heart disease. Relative risks and effect modification were calculated by the case-crossover method, a new epidemiologic technique designed to quantify the transient change in risk following exposure to a potential disease trigger. A total of 1774 patients with MI were interviewed in 45 hospitals throughout the United States. Data were gathered on potential triggers of MI occurring immediately prior to the event and during the previous year. Results are presented for the 858 patients who were sexually active in the year prior to the MI, with attention to the 273 patients who had coronary artery disease prior to their index MI, and the effect of regular exertion on risk. The relative risk of nonfatal MI following sexual activity. Of the 858 patients, 79(9%) reported sexual activity in the 24 hours preceding MI, and 27(3%) reported sexual activity in the 2 hours preceding onset of symptoms of MI. The relative risk of MI occurring in the 2 hours after sexual activity was 2.5(95% confidence interval [CI], 1.7-3.7). The relative risk of triggering onset of MI among patients with a history of prior angina (2.1 [95% CI, 0.8-5.8]) or prior MI (2.9 [95% CI, 1.3-6.5]) was not greater than that observed in those without prior cardiac disease. Sexual activity was a likely contributor to the onset of MI in only 0.9% of cases and regular exertion was associated with decreasing risk. Sexual activity can trigger the onset of MI. However, the relative risk is low, and since the absolute hourly risk of MI is extremely low, the absolute risk increase caused by sexual activity also is extremely low (1 chance in a million for a healthy individual). Moreover, the relative risk is not increased in patients with a prior history of cardiac disease and regular exercise appears to prevent triggering. These findings should be useful for counseling patients and decreasing the fear of sexual activity that often prevents complete rehabilitation from cardiovascular disease.

Early continuous ST segment monitoring in unstable angina: prognostic value additional to the clinical characteristics and the admission electrocardiogram.

In unstable angina, clinical characteristics, resting electrocardiography, and early continuous ST segment monitoring have been individually reported to identify subgroups at increased risk of adverse outcome. It is not known, however, whether continuous ST monitoring provides additional prognostic information in such a setting. Observational study of 212 patients with unstable angina without evidence of acute myocardial infarction admitted to district general hospitals, who had participated in a randomised study comparing heparin and aspirin treatment versus aspirin alone. Clinical variables and a 12 lead electrocardiogram (ECG) were recorded at admission, and treatment was standardised to include aspirin, atenolol, diltiazem, and intravenous glyceryl trinitrate, in addition to intravenous heparin (randomised treatment). Continuous ST segment monitoring was performed for 48 h and all inhospital adverse events were recorded. The admission ECG was normal in 61 patients (29%), showed ST depression in 59 (28%) (17 > or = 0.1 mV), and T wave changes in a further 69 (33%). The remaining 23 had Q waves (18), right bundle branch block (four), or ST elevation (one). During 8963 h of continuous ST segment monitoring (mean 42.3 h/patient), 132 episodes of transient myocardial ischaemia (104 silent) were recorded in 32 patients (15%). Forty patients (19%) had an adverse event (cardiac deaths (n = 3), non-fatal myocardial infarction (n = 6) and, emergency revascularisation (n = 31)). Both admission ECG ST depression (P = 0.02), and transient ischaemia (P < 0.001) predicted an increased risk of non-fatal myocardial infarction or death, while no patients with a normal ECG died or had a myocardial infarction. Adverse outcome was predicted by admission ECG ST depression (regardless of severity) (odds ratio (OR) 3.41) (P < 0.001), and maintenance beta blocker treatment (OR 2.95) (P < 0.01). A normal ECG predicted a favourable outcome (OR 0.38) (P = 0.04), while T wave or other ECG changes were not predictive of outcome. Transient ischaemia was the strongest predictor of adverse prognosis (OR 4.61) (P < 0.001), retaining independent predictive value in multivariate analysis (OR 2.94) (P = 0.03), as did maintenance beta blocker treatment (OR 2.85) (P = 0.01) and admission ECG ST depression, which showed a trend towards independent predictive value (OR 2.11) (P = 0.076). Patients with unstable angina and a normal admission ECG have a good prognosis, while ST segment depression predicts an adverse outcome. Transient myocardial ischaemia detected by continuous ST segment monitoring in such patients receiving optimal medical treatment provides prognostic information additional to that gleaned from the clinical characteristics or the admission ECG.

Physical Exercise and Reduced Risk of Nonfatal Myocardial Infarction

While the inverse association between physical activity and coronary heart disease risk is well documented, questions remain regarding the intensity of exercise, the potential for confounding by other risk factors for coronary heart disease, and the role of blood lipids and apolipoproteins. The authors examined these issues in the Boston Area Health Study, a case-control study of 340 patients (266 men, 74 women) who survived a first myocardial infarction between January 1, 1982, and December 31, 1983, and 340 controls matched on sex, age, and residence. The relative risk of myocardial infarction for those in the highest quartile of physical activity, compared with the lowest, was 0.50 (95 percent confidence interval (CI) 0.31-0.80) for men and 1.00 (95 percent CI 0.41-2.43) for women. When subjects were categorized by level of energy expenditure on moderate to vigorous sports alone, men in the most active category had 0.39 (95 percent CI 0.23-0.69) times the risk of those in the least active category, and women, 0.43 (95 percent CI 0.15-1.26) times the risk. Adjustment for body mass index, smoking, alcohol intake, diet, personal and family medical history, and personality type did not substantially change results nor did further adjustment for blood lipids. This was not surprising as total energy expenditure was uncorrelated with blood lipids or apolipoproteins. Moderate to vigorous sporting activity, however, appeared to be directly related to high density lipoprotein (HDL) cholesterol (p = 0.06), especially the HDL2 subfraction (p = 0.10). In these data, findings suggest that physical activity is inversely related to myocardial infarction risk, independently of other risk factors for coronary heart disease.

Leisure-Time Physical Activity and the Risk of Nonfatal Myocardial Infarction in Postmenopausal Women

Few studies have examined the association of physical activity with coronary heart disease among women. To examine whether participation in physical activity during leisure time decreases the risk of myocardial infarction in postmenopausal women. A population-based, case-control study among enrollees of the Group Health Cooperative of Puget Sound, a health maintenance organization based in Seattle, Wash. Cases were postmenopausal women who sustained an incident nonfatal myocardial infarction during the period 1986 through 1991. Controls were a random sample of Group Health Cooperative enrollees who were frequency matched to the cases by age and calendar year. Participation in physical activity during leisure time was assessed from a telephone interview. A total of 268 cases and 925 controls were interviewed. After adjustment for potential confounding factors, the odds ratios for nonfatal myocardial infarction for women in the second, third, and fourth quartile of total energy expenditure, relative to women in the first quartile, were 0.52 (95% confidence interval, 0.34 to 0.80), 0.40 (95% confidence interval, 0.26 to 0.63), and 0.40 (95% confidence interval, 0.25 to 0.63), respectively. Similar odds ratios were associated with the energy expended in nonstrenuous leisure-time physical activity, and with walking for exercise. This case-control study suggests that the risk of myocardial infarction among postmenopausal women is decreased by 50% with modest leisure-time energy expenditures, equivalent to 30 to 45 minutes of walking for exercise three times a week.