The threshold for myocardial ischemia varies in patients with coronary artery disease depending on the exercise protocol.

It is generally accepted that angina pectoris and, presumably, myocardial ischemia occur at a fixed heart rate-systolic blood pressure product in a given patient. This concept of a fixed threshold has recently been challenged. To evaluate the effects of varying exercise intensity on the ischemic threshold, 33 patients with coronary artery disease and provokable myocardial ischemia, documented by thallium-201 myocardial perfusion imaging, underwent two exercise tests 2 to 7 days apart. A symptom-limited incremental treadmill exercise test was followed by a 20 min submaximal treadmill test at an intensity approximating 70% of the peak heart rate attained during the incremental test. During the incremental exercise test, angina pectoris developed in 16 patients and 17 patients were asymptomatic. At least 0.1 mV of ST segment depression developed in all subjects during the incremental exercise test at a mean exercise duration of 5.3 +/- 2.6 min, a rate-pressure product of 19,130 +/- 5,735 and oxygen uptake of 19.6 +/- 7.0 ml/kg per min. During the submaximal exercise test, 28 (85%) of the 33 patients had significant ST segment depression. Of these patients, 24 (86%) were asymptomatic, including 10 patients who had previously reported anginal symptoms during the incremental test. The average time to onset of 0.1 mV ST segment depression during the submaximal test was 8.1 +/- 4.5 min. These changes occurred at a rate-pressure product of 15,250 +/- 3,705 and an oxygen uptake of 14.3 +/- 5.9 ml/kg per min, and were significantly (p less than 0.001) lower than values observed during the graded exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Aprindine therapy for refractory ventricular tachycardia.

Aprindine hydrochloride has been extensively used in Europe for the management of ventricular and supraventricular arrhythmias. Success has been achieved even in those cases that have proven refractory to standard antiarrhythmic agents. In this report, we describe our experience with aprindine therapy in seven patients with ventricular tachycardia in whom standard antiarrhythmic agents had proven either ineffective or had caused intolerable side effects. Aprindine was effective in five cases, and it failed in two. Neurologic side effects, although common, were easily controlled with adjustment of the dose. Agranulocytosis, a rare but serious side effect, was encountered in one of our patients. Relevant literature on aprindine is reviewed.

Labeling of participants in high blood pressure screening programs. Implications for blood cholesterol screenings.

Screening programs have expanded to identify the many persons who are unaware of their high blood cholesterol level and thus are at an increased risk for coronary heart disease. These programs bring both potential benefits and potential risks to the participant. One potential risk is that of iatrogenic effects of learning one's risk status, often referred to as the "labeling phenomenon." Research that has addressed the labeling phenomenon in blood pressure screening programs has important implications for blood cholesterol screenings. Detrimental effects on screening participants are possible, but they can be attenuated by careful attention to characteristics of the debriefing and counseling that should be included in screening protocols.

Mechanisms of hypercapneic pulmonary hypertension.

The mechanisms and potential mediator of hypercapneic pulmonary hypertension are incompletely understood. We studied 18 dogs, anaesthetised and spontaneously breathing both room air and after the inhalation of a gas mixture containing 10% CO2, 20.9% O2, and 69.1% N2, to determine the role of histamine, serotonin, and acidaemia in pulmonary hypertension produced by hypercapnia. Hypercapnia increased the mean pulmonary artery pressure by 0.33 kPa (2.5 mmHg) while wedge pressure and pulmonary arteriolar resistance did not change. Cardiac output significantly increased, indicating that the pulmonary hypertensive effect of hypercapnia is mainly flow related. Neither chlorpheniramine nor methysergide had significant effects on hypercapneic pulmonary hypertension. The infusion of sodium bicarbonate corrected the pH; pulmonary artery pressure and cardiac output increased while pulmonary arteriolar resistance dropped, suggesting that the increased cardiac output masked the effect of pH on pulmonary arteriolar resistance. The lack of effect of chlorpheniramine or methysergide on pulmonary resistances indicates that the vasoconstrictive effect of increased hydrogen ion concentration which accompanies hypercapnia is attributable neither to histamine nor to serotonin release.

Possible effect of DRGs on the classification of stroke: implications for epidemiological surveillance.

BACKGROUND AND PURPOSE: Accurate data on the distribution of stroke subtypes are essential for understanding the forces driving recent morbidity and mortality trends. The introduction of diagnosis-related groups (DRGs) in the 1980s may have affected the distribution of stroke subtypes as defined by International Classification of Diseases, Ninth Revision (ICD-9), discharge diagnosis codes. METHODS: The Pawtucket Heart Health Program cardiovascular surveillance data were used to examine trends in stroke classification for 1980 to 1991 in relation to the introduction of DRGs in 2 communities in Massachusetts and Rhode Island, where DRGs were implemented 2 years apart. Included were all hospital discharges for residents aged 35 to 74 with a primary ICD-9 diagnosis of 431 to 432, 434, or 436 to 437 (N=1386 in Rhode Island, N=1839 in Massachusetts). RESULTS: In each state, concurrently with the introduction of DRGs, the proportion of strokes classified as cerebral occlusion (ICD-9 434.0 to 434.9) increased, and the proportion classified as acute but ill-defined (ICD-9 436.0 to 436.9) decreased. Before DRGs, 30.0% of strokes in Rhode Island and 26.6% in Massachusetts were classified as cerebral occlusion, whereas 51.8% in Rhode Island and 51.7% in Massachusetts were classified as acute ill defined. After DRGs were instituted, the proportions of cerebral occlusion and acute, ill-defined stroke, respectively, were 70.9% and 8.5% in Rhode Island and 74.1% and 7.7% in Massachusetts (chi(2), all P<0.001). The proportions of strokes classified as intracerebral hemorrhage or transient cerebral ischemia remained constant. CONCLUSIONS: The implementation of DRGs may have influenced coding of strokes to the ICD-9. Findings highlight the limitations of hospital discharge data for evaluating stroke subtypes and demonstrate the need for community-based surveillance for monitoring specific trends in stroke.

Effect of exercise training on the untrained limb exercise performance of men with angina pectoris.

This study examined the exercise capacity of trained and untrained limbs in men with angina pectoris before and after 8 weeks of arm ( n = 4) or leg (n = 7) physical training or a control (n = 4) period. Time to angina (mean +/- standard deviation) increased 3.6 +/- 2.7 minutes (p less than 0.01) during trained limb and 1.6 +/- 1.2 minutes (p less than 0.01) during untrained limb exercise. Myocardial oxygen demand at angina estimated by the product of heart rate and systolic blood pressure did not change with training. At a constant subanginal work load, rate-pressure product x 10(-2) was reduced by 35 +/- 22 (p less than 0.001) during trained limb and by 18 +/- 27 (p less than 0.05) during untrained limb exercise. The decrease in rate-pressure product with both trained and untrained limbs was greatest in subjects with the highest rate-pressure product at angina before training. Control subjects showed no change in any exercise measurement. Exercise training increases the exercise capacity of untrained limbs in patients with angina pectoris by a generalized training effect not dependent on adaptations in trained skeletal muscle. The improvement for both trained and untrained limbs results from a reduced rate-pressure product at subanginal work loads rather than from an increase in myocardial oxygen delivery. Subjects with the highest pretraining coronary arterial oxygen supply at the onset of angina benefit most from physical training.

Combined hyertrophic subaortic stenosis and calcific aortic valvular stenosis.

A well documented case of combined hypertrophic subaortic stenosis and calcific aortic stenosis is reported. Detection of multilevel involvement in cases of left ventricular outflow obstruction requires a high index of suspicion and precise hemodynamic and angiographic documentation. Careful analysis of the total data base is necessary for proper management of the patient. The pathogenesis of this combined lesion is unclear: Asymmetrical septal hypertrophy may occur as a consequence of the valvular stenosis, or it may be that abnormal leaflet motion in patients with hypertrophic obstruction produces leaflet thickening, calcification, deformity and stenosis.

Plasma beta-endorphin levels in silent myocardial ischemia induced by exercise.

Although silent myocardial ischemia is a well recognized phenomenon, the reasons for the lack of symptoms in patients with coronary artery disease (CAD) is unclear. Because the endogenous opioid beta-endorphin has been related to pain modulation, plasma beta-endorphin levels were studied before, during and after exercise-induced ischemia in symptomatic and asymptomatic men. Because beta-endorphin responses have been closely linked to adrenocorticotropic hormone (ACTH) and cortisol responses, these hormones also were measured. Nine symptomatic and 12 asymptomatic patients with a high probability (at least 95%) of CAD and 8 apparently healthy men completed a Bruce protocol treadmill test. Blood samples were drawn before, during and 10 minutes after exercise. During exercise the measured hormones showed no significant increases from basal levels. However, plasma beta-endorphin, ACTH and cortisol levels were significantly elevated (p less than or equal to 0.01) 10 minutes after exercise in all 3 groups. There was no significant difference in plasma beta-endorphin levels during or after exercise between the symptomatic and asymptomatic patients with CAD. Thus, differences in circulating levels of beta-endorphin, ACTH and cortisol are not associated with the presence or absence of pain during exercise-induced myocardial ischemia.

HDL cholesterol: trends in two southeastern New England communities, 1981-1993.

PURPOSE: Although public health interventions have not specifically targeted high density lipoprotein (HDL) cholesterol, observed changes in the prevalence of other cardiovascular risk factors would be expected to have differential effects on HDL. This study examined secular trends in HDL in relation to changes in other cardiovascular risk factors for the years 1981 through 1993 in the Pawtucket Heart Health Program (PHHP) study communities. METHODS: Nonfasting HDL levels were assessed in 12,223 respondents to six biennial population random sample surveys. RESULTS: Between 1981 and 1993, mean HDL cholesterol declined by 0.08 mmol/L in both men and women after adjustment for age, city, education, hormone use, medications, recent alcohol use, smoking, regular exercise, body mass index (BMI), and total cholesterol, (p for trend < 0.001). There was no apparent laboratory explanation for the trend which occurred concurrent with decreased smoking prevalence, increasing BMI and decreased prevalence of recent alcohol use. Decreasing HDL cholesterol was observed consistently across subgroups defined by smoking, alcohol use and BMI. CONCLUSIONS: Although several favorable cardiovascular risk factor trends have been observed in recent decades, declining HDL cholesterol is also of interest, particularly in conjunction with population increases in BMI.

Comparison of "Rose Questionnaire Angina" to exercise thallium scintigraphy: different findings in males and females.

Validation of the London School of Hygiene (Rose) Questionnaire with objective measures of myocardial ischemia is incomplete. Therefore, we compared the Rose Questionnaire with exercise thallium-201 myocardial scintigraphy in 147 male and 97 female patients with chest pain referred for clinical exercise testing. Of those with "Rose Questionnaire angina", 26% of the females and 73% of the males had positive thallium-201 scans. Negative results on both the Rose Questionnaire and thallium-201 scintigraphy were observed in 71% of the females and 47% of the males. The sensitivity of the Rose Questionnaire was similar in females (41%) and males (44%). The specificity was 77% in males, while in females it was significantly lower at 56%. The specificity values reflect the higher (p less than 0.05) prevalence of "false positive" Rose Questionnaire results in females (75%) compared with males (27%). In addition, males had a greater (p less than 0.05) number of "false negative" results (53%) than females (29%). The accuracy of the Rose Questionnaire for myocardial ischemia was 0.19 in females, 0.48 in males, and 0.29 overall when including both males and females. Our results indicate a generally poor relationship between Rose Questionnaire angina and thallium-201 scintigraphy, an objective measure of myocardial ischemia in patients with chest pain referred to clinical exercise testing. Further, there are gender-specific differences in this relationship between the questionnaire and exercise thallium-201 imaging.

Coronary heart disease surveillance: field application of an epidemiologic algorithm.

This report describes the performance of a surveillance system and computerized algorithm for the assignment of definite or probable hospitalized cardiac events for large epidemiologic studies. The algorithm, developed by the Coordinating Committee for Community Demonstration Studies (CCCDS), evolved from the Gillum criteria, and included selected ICD-9-CM codes including codes 410 through 414 for discharge record screening, plus creatine kinase. For the small percentage of cases in which enzyme analysis was inconclusive (8%), presence of pain and/or Minnesota-coded electrocardiograms were included to define the outcome. All data items were easily obtained from medical records by trained lay record abstractors and required no interpretation. From January 1980 through December 1991, 21,183 medical records were screened for ICD-9-CM codes 410 through 414. Of all 410 to 411 ICD-9-CM codes (n = 9026), 36.9% (n = 3220) were classified as definite cardiac events and 10.6% (n = 1057) as probable events. Of all 412 through 414 codes (n = 9070), only 1.8% (n = 227) were classified as definite cardiac events and 5.4% (n = 716) as probable events. The epidemiologic diagnostic algorithm presented in this article used computerized data to assign diagnoses in a standard, objective manner, and was a lower cost alternative to classification of cardiac events on the basis of clinical review and/or more complex record abstraction approaches.

Wenckebach (type 1) behavior of ventricular reentry.

Electrocardiographic excerpts from three patients demonstrate bigeminy, concealed bigeminy, trigeminy, concealed trigeminy, and Wenckebach's pattern of variation in the coupling interval from sinus beat to ventricular ectopic beat. These diverse manifestations of ventricular ectopy support the hypothesis that reentry in man reflects conduction of an initial impulse, with delay, to cause the coupled reentrant beat.

A new approach to surveillance for acute myocardial infarction: reproducibility and cost efficiency.

A new approach to surveillance of myocardial infarction, the major cardiovascular endpoint is described using an algorithm which depends primarily on enzyme data, using evidence of chest pain and positive electrocardiogram findings as supplemental information only. This approach is evaluated with respect to reproducibility by minimally trained abstractors, cost, and robustness with respect to different hospital systems as well as changes in diagnostic techniques and/or labelling over time. Two pilot studies demonstrate that, in comparison to more traditional approaches, the new surveillance system provides at least a 50% reduction in cost, is highly reproducible over different hospital systems, and potentially, is resilient to changes in diagnostic procedures or coding. The more general applicability of such an innovative surveillance approach to other disease endpoints, in which one reliable procedure contains most of the diagnostic information, is discussed with particular reference to cancer.

Short stature and cardiovascular disease among men and women from two southeastern New England communities.

BACKGROUND: Short stature has been associated with an increased risk of coronary heart disease (CHD), although the reason for the association remains unclear. Data on the relation between stature and stroke is more limited. We examined the association between stature and CHD as well as between stature and stroke in men and women from two communities in southeastern New England. METHODS: Coronary heart disease and stroke events were abstracted from medical records between January 1980 and December 1991. An epidemiological diagnostic algorithm developed to measure CHD was used in the present analysis. Unadjusted relative risks (RR) and RR adjusted for age, smoking status, obesity, high-density lipoprotein (HDL) cholesterol <0.91 mmol/l, total cholesterol >6.21 mmol/l, hypertension, diabetes, education, and being foreign born were computed by gender-specific height categories separately for men (n = 2826) and women (n = 3741). RESULTS: A graded inverse association between stature and risk of CHD was observed among men which persisted after adjustment for confounders. Men >69.75 inches had an 83% lower risk of CHD compared with men < or = 65 inches. In addition, the tallest men had a 67% decreased risk of stroke compared with the shortest men. No significant relation between stature and CHD or stroke was observed among women. CONCLUSIONS: These data support the hypothesis that stature is inversely related to both risk of CHD and stroke at least among men. Factors which might explain this association remain to be determined.

Self-reported alcohol intake using two different question formats in southeastern New England.

BACKGROUND: Quantitative measures of alcohol intake are not always available in population studies. METHOD: The authors evaluated whether a question on alcohol intake embedded within a general health survey could be used as a surrogate marker for alcohol intake. We compared alcohol intake assessed with a food frequency questionnaire (FFQ) with alcohol intake assessed with a simple dichotomous survey question in a population-based sample. RESULTS: The study population consisted of 755 men and 1164 women from two communities in southeastern New England in the USA. There was strong agreement between the two alcohol questions for the classification of nondrinkers (98.1%). When participants were classified according to the quantity of alcohol consumed on the FFQ, the ability of the simple question to identify drinkers improved in a dose-response fashion. The Kappa statistic was 0.08 (P < 0.001), 0.38 (P < 0.001), and 0.81 (P < 0.001) for low, medium, and high consumers of alcohol, respectively. CONCLUSIONS: These results suggest that the survey alcohol question provides a useful qualitative measure of categorizing nondrinkers and identifying drinkers who consume more than one drink per day. In population studies where quantitative measures of alcohol intake may not be available a survey alcohol question may prove useful when alcohol intake is likely to confound results, and adjustment of the data is needed.

The Pawtucket Heart Health Program. Influencing adolescent eating patterns.

The Pawtucket Heart Health Program, a research effort testing a process of community activation for cardiovascular risk factor behavior change, risk factor change, and coronary heart disease event rate change, utilizes risk factor behavior change programs for the entire population of a northeastern city. A diversity of nutrition programs designed to teach new skills and to alter the nutrition environment have been delivered. These include group programs, highlighting restaurant menus, labeling grocery shelf items, screening for blood cholesterol levels accompanied by nutritional counseling, and provision of programs in schools. In addition to standard curricula, the Heart Healthy Cook-Off for both junior high school and high school students has been developed. Students select recipes, make substitutions to lower fat, saturated fat, and cholesterol content, analyze original and substitution recipe nutrient content using a microcomputer and nutrient analysis software, and prepare the food. A panel of judges assesses presentation, taste, and health-promoting characteristics. In one junior high school class, cholesterol measure before and after the cook-off decreased by 10.7% among those with elevated cholesterol. The Heart Healthy Cook-Off is an education program that influences the culinary practices of children in an enjoyable, challenging format.

Atrioventricular sequential pacemakers: indications, complications, and long-term follow-up.

Our experience with 32 patients with atrioventricular (AV) sequential pacemakers and an average follow-up of 22 months is presented. The pertinent literature and physiology are reviewed. The indications, advantages, and complications of AV sequential pacemakers are analyzed. Half of the patients required bifocal pacing for control of arrhythmia alone, while half required control of arrhythmia associated with congestive heart failure due primarily to a noncompliant left ventricle. It is anticipated that the hemodynamic improvement occurring as a results of AV sequential pacing will increase the use of this mode of cardiac pacing in selected patients.

Correlates of expected success at health habit change and its role as a predictor in health behavior research.

Perceived ability to change health habits successfully is undoubtedly an important factor underlying personal health behavior. This report examines expected success in changing future habits, using a sample of community-resident adults 18-65 years of age (n = 1,367). One set of analyses used expected success as a dependent variable, whereas another set used it as an independent variable for health behavior and knowledge indices. In the dependent variable analysis, results showed that reported past success at health habit change was the strongest predictor of success expected in the future. Optimism about future success was also associated with variables that already placed individuals at an advantage to change behavior (e.g., not smoking, regular exercise, lower Body Mass Index, support in the family). When used as a predictor variable, expected future success was not associated with five health-related, self-report indices of behavior, knowledge, and perceived risk. Further examination showed, however, that in three instances the association between expected success and the outcome indices seemed to plateau in the most optimistic group. Extreme optimism (that admits no chance of failure) may be a belief characteristic that deserves further investigation, one that will present a challenge to research and practice. Men tended to report greater expected future success than women, although women had more favorable reports on three of the five health-related behavior/knowledge indices.

Training volunteers to conduct heart health programs in churches.

With cardiovascular disease the leading cause of death and disability in the United States, economically feasible and effective methods of prevention are needed. The Health and Religion Project (HARP) uses volunteers to provide cardiovascular risk-factor change programs to individuals in their church communities. The rationale for the use of volunteers in this setting is described, along with the design and initial response to the HARP volunteer training program. Two hundred twenty-two volunteers were certified across 16 study churches to conduct risk-factor change programs. Their certification exam performance demonstrated that they had mastered the knowledge and skills deemed necessary for their jobs. Overall, the trainees were very enthusiastic about their new roles. Based on this initial response, our partnership with churches for health promotion is worthy of further development.

Promoting the selection of healthy food through menu item description in a family-style restaurant.

We describe an attempt to influence the selection of menu items in a family-style restaurant. Three different messages, varying in content and emphasis, were used to promote one food special each intervention day. One message emphasized that the specials were particularly healthful, being relatively low in fat, sodium, and cholesterol. A second message stressed flavor and added that the choice was healthful. A third, nonspecific message made no mention of taste or health factors, but simply noted that there was a daily special. Results indicated that restaurant patrons selected healthful specials when the message noted that the choice was healthful but emphasized flavor. Patrons were apparently more open to information about the palatability of the food than its healthfulness per se. These results have implications for point-of-purchase health promotion efforts in general, especially those involving food-labeling programs in restaurants and grocery stores.